// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
package com.cloud.storage;

import java.math.BigDecimal;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.UnknownHostException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.UUID;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import javax.ejb.Local;
import javax.inject.Inject;
import javax.naming.ConfigurationException;

import org.apache.cloudstack.api.command.admin.storage.CancelPrimaryStorageMaintenanceCmd;
import org.apache.cloudstack.api.command.admin.storage.CreateStoragePoolCmd;
import org.apache.cloudstack.api.command.admin.storage.DeletePoolCmd;
import org.apache.cloudstack.api.command.admin.storage.UpdateStoragePoolCmd;
import org.apache.cloudstack.api.command.user.volume.CreateVolumeCmd;
import org.apache.cloudstack.api.command.user.volume.UploadVolumeCmd;
import org.apache.cloudstack.api.command.user.volume.ResizeVolumeCmd;
import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;

import com.cloud.agent.AgentManager;
import com.cloud.agent.api.*;
import com.cloud.agent.api.storage.*;
import com.cloud.agent.api.to.StorageFilerTO;
import com.cloud.agent.api.to.VolumeTO;
import com.cloud.agent.manager.Commands;
import com.cloud.alert.AlertManager;
import com.cloud.api.ApiDBUtils;
import com.cloud.async.AsyncJobManager;
import com.cloud.capacity.Capacity;
import com.cloud.capacity.CapacityManager;
import com.cloud.capacity.CapacityState;
import com.cloud.capacity.CapacityVO;
import com.cloud.capacity.dao.CapacityDao;
import com.cloud.cluster.ClusterManagerListener;
import com.cloud.cluster.ManagementServerHostVO;
import com.cloud.configuration.Config;
import com.cloud.configuration.ConfigurationManager;
import com.cloud.configuration.Resource.ResourceType;
import com.cloud.configuration.dao.ConfigurationDao;
import com.cloud.consoleproxy.ConsoleProxyManager;
import com.cloud.dc.ClusterVO;
import com.cloud.dc.DataCenterVO;
import com.cloud.dc.HostPodVO;
import com.cloud.dc.Pod;
import com.cloud.dc.dao.ClusterDao;
import com.cloud.dc.dao.DataCenterDao;
import com.cloud.dc.dao.HostPodDao;
import com.cloud.deploy.DeployDestination;
import com.cloud.domain.Domain;
import com.cloud.domain.dao.DomainDao;
import com.cloud.event.ActionEvent;
import com.cloud.event.EventTypes;
import com.cloud.event.UsageEventUtils;
import com.cloud.event.dao.EventDao;
import com.cloud.exception.*;
import com.cloud.host.Host;
import com.cloud.host.HostVO;
import com.cloud.host.Status;
import com.cloud.host.dao.HostDao;
import com.cloud.hypervisor.Hypervisor.HypervisorType;
import com.cloud.hypervisor.HypervisorGuruManager;
import com.cloud.network.NetworkModel;
import com.cloud.offering.ServiceOffering;
import com.cloud.org.Grouping;
import com.cloud.org.Grouping.AllocationState;
import com.cloud.resource.ResourceManager;
import com.cloud.resource.ResourceState;
import com.cloud.server.ManagementServer;
import com.cloud.server.StatsCollector;
import com.cloud.service.ServiceOfferingVO;
import com.cloud.service.dao.ServiceOfferingDao;
import com.cloud.storage.Storage.ImageFormat;
import com.cloud.storage.Storage.StoragePoolType;
import com.cloud.storage.Volume.Event;
import com.cloud.storage.Volume.Type;
import com.cloud.storage.allocator.StoragePoolAllocator;
import com.cloud.storage.dao.*;
import com.cloud.storage.download.DownloadMonitor;
import com.cloud.storage.listener.StoragePoolMonitor;
import com.cloud.storage.listener.VolumeStateListener;
import com.cloud.storage.s3.S3Manager;
import com.cloud.storage.secondary.SecondaryStorageVmManager;
import com.cloud.storage.snapshot.SnapshotManager;
import com.cloud.storage.snapshot.SnapshotScheduler;
import com.cloud.tags.dao.ResourceTagDao;
import com.cloud.template.TemplateManager;
import com.cloud.user.*;
import com.cloud.user.dao.AccountDao;
import com.cloud.user.dao.UserDao;
import com.cloud.uservm.UserVm;
import com.cloud.utils.EnumUtils;
import com.cloud.utils.NumbersUtil;
import com.cloud.utils.Pair;
import com.cloud.utils.UriUtils;
import com.cloud.utils.component.ComponentContext;
import com.cloud.utils.component.Manager;
import com.cloud.utils.component.ManagerBase;
import com.cloud.utils.concurrency.NamedThreadFactory;
import com.cloud.utils.db.*;
import com.cloud.utils.db.JoinBuilder.JoinType;
import com.cloud.utils.db.SearchCriteria.Op;
import com.cloud.utils.exception.CloudRuntimeException;
import com.cloud.utils.exception.ExecutionException;
import com.cloud.utils.fsm.NoTransitionException;
import com.cloud.utils.fsm.StateMachine2;
import com.cloud.vm.*;
import com.cloud.vm.VirtualMachine.State;
import com.cloud.vm.dao.*;

@Component
@Local(value = { StorageManager.class, StorageService.class })
public class StorageManagerImpl extends ManagerBase implements StorageManager, ClusterManagerListener {
    private static final Logger s_logger = Logger.getLogger(StorageManagerImpl.class);

    protected String _name;
    @Inject
    protected UserVmManager _userVmMgr;
    @Inject
    protected AgentManager _agentMgr;
    @Inject
    protected TemplateManager _tmpltMgr;
    @Inject
    protected AsyncJobManager _asyncMgr;
    @Inject
    protected SnapshotManager _snapshotMgr;
    @Inject
    protected SnapshotScheduler _snapshotScheduler;
    @Inject
    protected AccountManager _accountMgr;
    @Inject
    protected ConfigurationManager _configMgr;
    @Inject
    protected ConsoleProxyManager _consoleProxyMgr;
    @Inject
    protected SecondaryStorageVmManager _secStorageMgr;
    @Inject
    protected NetworkModel _networkMgr;
    @Inject
    protected VolumeDao _volsDao;
    @Inject
    protected HostDao _hostDao;
    @Inject
    protected ConsoleProxyDao _consoleProxyDao;
    @Inject
    protected SnapshotDao _snapshotDao;
    @Inject
    protected SnapshotManager _snapMgr;
    @Inject
    protected SnapshotPolicyDao _snapshotPolicyDao;
    @Inject
    protected StoragePoolHostDao _storagePoolHostDao;
    @Inject
    protected AlertManager _alertMgr;
    @Inject
    protected VMTemplateHostDao _vmTemplateHostDao = null;
    @Inject
    protected VMTemplatePoolDao _vmTemplatePoolDao = null;
    @Inject
    protected VMTemplateSwiftDao _vmTemplateSwiftDao = null;
    @Inject
    protected VMTemplateS3Dao _vmTemplateS3Dao;
    @Inject
    protected S3Manager _s3Mgr;
    @Inject
    protected VMTemplateDao _vmTemplateDao = null;
    @Inject
    protected StoragePoolHostDao _poolHostDao = null;
    @Inject
    protected UserVmDao _userVmDao;
    @Inject
    VolumeHostDao _volumeHostDao;
    @Inject
    protected VMInstanceDao _vmInstanceDao;
    @Inject
    protected StoragePoolDao _storagePoolDao = null;
    @Inject
    protected CapacityDao _capacityDao;
    @Inject
    protected CapacityManager _capacityMgr;
    @Inject
    protected DiskOfferingDao _diskOfferingDao;
    @Inject
    protected AccountDao _accountDao;
    @Inject
    protected EventDao _eventDao = null;
    @Inject
    protected DataCenterDao _dcDao = null;
    @Inject
    protected HostPodDao _podDao = null;
    @Inject
    protected VMTemplateDao _templateDao;
    @Inject
    protected VMTemplateHostDao _templateHostDao;
    @Inject
    protected ServiceOfferingDao _offeringDao;
    @Inject
    protected DomainDao _domainDao;
    @Inject
    protected UserDao _userDao;
    @Inject
    protected ClusterDao _clusterDao;
    @Inject
    protected VirtualMachineManager _vmMgr;
    @Inject
    protected DomainRouterDao _domrDao;
    @Inject
    protected SecondaryStorageVmDao _secStrgDao;
    @Inject
    protected StoragePoolWorkDao _storagePoolWorkDao;
    @Inject
    protected HypervisorGuruManager _hvGuruMgr;
    @Inject
    protected VolumeDao _volumeDao;
    @Inject
    protected OCFS2Manager _ocfs2Mgr;
    @Inject
    protected ResourceLimitService _resourceLimitMgr;
    @Inject
    protected SecondaryStorageVmManager _ssvmMgr;
    @Inject
    protected ResourceManager _resourceMgr;
    @Inject
    protected DownloadMonitor _downloadMonitor;
    @Inject
    protected ResourceTagDao _resourceTagDao;
    @Inject
    protected List<StoragePoolAllocator> _storagePoolAllocators;
    @Inject ConfigurationDao _configDao;
    @Inject ManagementServer _msServer;

    // TODO : we don't have any instantiated pool discover, disable injection temporarily
    // @Inject
    protected List<StoragePoolDiscoverer> _discoverers;


    protected SearchBuilder<VMTemplateHostVO> HostTemplateStatesSearch;
    protected GenericSearchBuilder<StoragePoolHostVO, Long> UpHostsInPoolSearch;
    protected SearchBuilder<VMInstanceVO> StoragePoolSearch;
    protected SearchBuilder<StoragePoolVO> LocalStorageSearch;

    ScheduledExecutorService _executor = null;
    boolean _storageCleanupEnabled;
    boolean _templateCleanupEnabled = true;
    int _storageCleanupInterval;
    private int _createVolumeFromSnapshotWait;
    private int _copyvolumewait;
    int _storagePoolAcquisitionWaitSeconds = 1800; // 30 minutes
    protected int _retry = 2;
    protected int _pingInterval = 60; // seconds
    protected int _hostRetry;
    protected BigDecimal _overProvisioningFactor = new BigDecimal(1);
    private long _maxVolumeSizeInGb;
    private long _serverId;
    private final StateMachine2<Volume.State, Volume.Event, Volume> _volStateMachine;
    private int _customDiskOfferingMinSize = 1;
    private int _customDiskOfferingMaxSize = 1024;
    private double _storageUsedThreshold = 1.0d;
    private double _storageAllocatedThreshold = 1.0d;
    protected BigDecimal _storageOverprovisioningFactor = new BigDecimal(1);

    private boolean _recreateSystemVmEnabled;

    public boolean share(VMInstanceVO vm, List<VolumeVO> vols, HostVO host, boolean cancelPreviousShare) throws StorageUnavailableException {

        // if pool is in maintenance and it is the ONLY pool available; reject
        List<VolumeVO> rootVolForGivenVm = _volsDao.findByInstanceAndType(vm.getId(), Type.ROOT);
        if (rootVolForGivenVm != null && rootVolForGivenVm.size() > 0) {
            boolean isPoolAvailable = isPoolAvailable(rootVolForGivenVm.get(0).getPoolId());
            if (!isPoolAvailable) {
                throw new StorageUnavailableException("Can not share " + vm, rootVolForGivenVm.get(0).getPoolId());
            }
        }

        // this check is done for maintenance mode for primary storage
        // if any one of the volume is unusable, we return false
        // if we return false, the allocator will try to switch to another PS if available
        for (VolumeVO vol : vols) {
            if (vol.getRemoved() != null) {
                s_logger.warn("Volume id:" + vol.getId() + " is removed, cannot share on this instance");
                // not ok to share
                return false;
            }
        }

        // ok to share
        return true;
    }

    @Override
    public VolumeVO allocateDuplicateVolume(VolumeVO oldVol, Long templateId) {
        VolumeVO newVol = new VolumeVO(oldVol.getVolumeType(), oldVol.getName(), oldVol.getDataCenterId(), oldVol.getDomainId(), oldVol.getAccountId(), oldVol.getDiskOfferingId(), oldVol.getSize());
        if (templateId != null) {
            newVol.setTemplateId(templateId);
        } else {
            newVol.setTemplateId(oldVol.getTemplateId());
        }
        newVol.setDeviceId(oldVol.getDeviceId());
        newVol.setInstanceId(oldVol.getInstanceId());
        newVol.setRecreatable(oldVol.isRecreatable());
        return _volsDao.persist(newVol);
    }

    private boolean isPoolAvailable(Long poolId) {
        // get list of all pools
        List<StoragePoolVO> pools = _storagePoolDao.listAll();

        // if no pools or 1 pool which is in maintenance
        if (pools == null || pools.size() == 0 || (pools.size() == 1 && pools.get(0).getStatus().equals(StoragePoolStatus.Maintenance))) {
            return false;
        } else {
            return true;
        }
    }

    @Override
    public List<StoragePoolVO> ListByDataCenterHypervisor(long datacenterId, HypervisorType type) {
        List<StoragePoolVO> pools = _storagePoolDao.listByDataCenterId(datacenterId);
        List<StoragePoolVO> retPools = new ArrayList<StoragePoolVO>();
        for (StoragePoolVO pool : pools) {
            if (pool.getStatus() != StoragePoolStatus.Up) {
                continue;
            }
            ClusterVO cluster = _clusterDao.findById(pool.getClusterId());
            if (type == cluster.getHypervisorType()) {
                retPools.add(pool);
            }
        }
        Collections.shuffle(retPools);
        return retPools;
    }

    @Override
    public boolean isLocalStorageActiveOnHost(Long hostId) {
        List<StoragePoolHostVO> storagePoolHostRefs = _storagePoolHostDao.listByHostId(hostId);
        for (StoragePoolHostVO storagePoolHostRef : storagePoolHostRefs) {
            StoragePoolVO storagePool = _storagePoolDao.findById(storagePoolHostRef.getPoolId());
            if (storagePool.getPoolType() == StoragePoolType.LVM || storagePool.getPoolType() == StoragePoolType.EXT) {
                SearchBuilder<VolumeVO> volumeSB = _volsDao.createSearchBuilder();
                volumeSB.and("poolId", volumeSB.entity().getPoolId(), SearchCriteria.Op.EQ);
                volumeSB.and("removed", volumeSB.entity().getRemoved(), SearchCriteria.Op.NULL);

                SearchBuilder<VMInstanceVO> activeVmSB = _vmInstanceDao.createSearchBuilder();
                activeVmSB.and("state", activeVmSB.entity().getState(), SearchCriteria.Op.IN);
                volumeSB.join("activeVmSB", activeVmSB, volumeSB.entity().getInstanceId(), activeVmSB.entity().getId(), JoinBuilder.JoinType.INNER);

                SearchCriteria<VolumeVO> volumeSC = volumeSB.create();
                volumeSC.setParameters("poolId", storagePool.getId());
                volumeSC.setJoinParameters("activeVmSB", "state", State.Starting, State.Running, State.Stopping, State.Migrating);

                List<VolumeVO> volumes = _volsDao.search(volumeSC, null);
                if (volumes.size() > 0) {
                    return true;
                }
            }
        }

        return false;
    }

    protected StoragePoolVO findStoragePool(DiskProfile dskCh, final DataCenterVO dc, HostPodVO pod, Long clusterId, Long hostId, VMInstanceVO vm, final Set<StoragePool> avoid) {

        VirtualMachineProfile<VMInstanceVO> profile = new VirtualMachineProfileImpl<VMInstanceVO>(vm);
        for (StoragePoolAllocator allocator : _storagePoolAllocators) {
            final List<StoragePool> poolList = allocator.allocateToPool(dskCh, profile, dc.getId(), pod.getId(), clusterId, hostId, avoid, 1);
            if (poolList != null && !poolList.isEmpty()) {
                return (StoragePoolVO) poolList.get(0);
            }
        }
        return null;
    }

    @Override
    public Answer[] sendToPool(StoragePool pool, Commands cmds) throws StorageUnavailableException {
        return sendToPool(pool, null, null, cmds).second();
    }

    @Override
    public Answer sendToPool(StoragePool pool, long[] hostIdsToTryFirst, Command cmd) throws StorageUnavailableException {
        Answer[] answers = sendToPool(pool, hostIdsToTryFirst, null, new Commands(cmd)).second();
        if (answers == null) {
            return null;
        }
        return answers[0];
    }

    @Override
    public Answer sendToPool(StoragePool pool, Command cmd) throws StorageUnavailableException {
        Answer[] answers = sendToPool(pool, new Commands(cmd));
        if (answers == null) {
            return null;
        }
        return answers[0];
    }

    @Override
    public Answer sendToPool(long poolId, Command cmd) throws StorageUnavailableException {
        StoragePool pool = _storagePoolDao.findById(poolId);
        return sendToPool(pool, cmd);
    }

    @Override
    public Answer[] sendToPool(long poolId, Commands cmds) throws StorageUnavailableException {
        StoragePool pool = _storagePoolDao.findById(poolId);
        return sendToPool(pool, cmds);
    }

    protected DiskProfile createDiskCharacteristics(VolumeVO volume, VMTemplateVO template, DataCenterVO dc, DiskOfferingVO diskOffering) {
        if (volume.getVolumeType() == Type.ROOT && Storage.ImageFormat.ISO != template.getFormat()) {
            SearchCriteria<VMTemplateHostVO> sc = HostTemplateStatesSearch.create();
            sc.setParameters("id", template.getId());
            sc.setParameters("state", com.cloud.storage.VMTemplateStorageResourceAssoc.Status.DOWNLOADED);
            sc.setJoinParameters("host", "dcId", dc.getId());

            List<VMTemplateHostVO> sss = _vmTemplateHostDao.search(sc, null);
            if (sss.size() == 0) {
                throw new CloudRuntimeException("Template " + template.getName() + " has not been completely downloaded to zone " + dc.getId());
            }
            VMTemplateHostVO ss = sss.get(0);

            return new DiskProfile(volume.getId(), volume.getVolumeType(), volume.getName(), diskOffering.getId(), ss.getSize(), diskOffering.getTagsArray(), diskOffering.getUseLocalStorage(),
                    diskOffering.isRecreatable(), Storage.ImageFormat.ISO != template.getFormat() ? template.getId() : null);
        } else {
            return new DiskProfile(volume.getId(), volume.getVolumeType(), volume.getName(), diskOffering.getId(), diskOffering.getDiskSize(), diskOffering.getTagsArray(),
                    diskOffering.getUseLocalStorage(), diskOffering.isRecreatable(), null);
        }
    }

    @Override
    public boolean canVmRestartOnAnotherServer(long vmId) {
        List<VolumeVO> vols = _volsDao.findCreatedByInstance(vmId);
        for (VolumeVO vol : vols) {
            if (!vol.isRecreatable() && !vol.getPoolType().isShared()) {
                return false;
            }
        }
        return true;
    }

    @DB
    protected Pair<VolumeVO, String> createVolumeFromSnapshot(VolumeVO volume, SnapshotVO snapshot) {
        VolumeVO createdVolume = null;
        Long volumeId = volume.getId();

        String volumeFolder = null;

        try {
            stateTransitTo(volume, Volume.Event.CreateRequested);
        } catch (NoTransitionException e) {
            s_logger.debug(e.toString());
            return null;
        }
        // Create the Volume object and save it so that we can return it to the user
        Account account = _accountDao.findById(volume.getAccountId());

        final HashSet<StoragePool> poolsToAvoid = new HashSet<StoragePool>();
        StoragePoolVO pool = null;
        boolean success = false;
        Set<Long> podsToAvoid = new HashSet<Long>();
        Pair<HostPodVO, Long> pod = null;
        String volumeUUID = null;
        String details = null;

        DiskOfferingVO diskOffering = _diskOfferingDao.findByIdIncludingRemoved(volume.getDiskOfferingId());
        DataCenterVO dc = _dcDao.findById(volume.getDataCenterId());
        DiskProfile dskCh = new DiskProfile(volume, diskOffering, snapshot.getHypervisorType());

        int retry = 0;
        // Determine what pod to store the volume in
        while ((pod = _resourceMgr.findPod(null, null, dc, account.getId(), podsToAvoid)) != null) {
            podsToAvoid.add(pod.first().getId());
            // Determine what storage pool to store the volume in
            while ((pool = findStoragePool(dskCh, dc, pod.first(), null, null, null, poolsToAvoid)) != null) {
                poolsToAvoid.add(pool);
                volumeFolder = pool.getPath();
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("Attempting to create volume from snapshotId: " + snapshot.getId() + " on storage pool " + pool.getName());
                }

                // Get the newly created VDI from the snapshot.
                // This will return a null volumePath if it could not be created
                Pair<String, String> volumeDetails = createVDIFromSnapshot(UserContext.current().getCallerUserId(), snapshot, pool);

                volumeUUID = volumeDetails.first();
                details = volumeDetails.second();

                if (volumeUUID != null) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("Volume with UUID " + volumeUUID + " was created on storage pool " + pool.getName());
                    }
                    success = true;
                    break; // break out of the "find storage pool" loop
                } else {
                    retry++;
                    if (retry >= 3) {
                        _volsDao.expunge(volumeId);
                        String msg = "Unable to create volume from snapshot " + snapshot.getId() + " after retrying 3 times, due to " + details;
                        s_logger.debug(msg);
                        throw new CloudRuntimeException(msg);

                    }
                }
                s_logger.warn("Unable to create volume on pool " + pool.getName() + ", reason: " + details);
            }

            if (success) {
                break; // break out of the "find pod" loop
            }
        }

        if (!success) {
            _volsDao.expunge(volumeId);
            String msg = "Unable to create volume from snapshot " + snapshot.getId() + " due to " + details;
            s_logger.debug(msg);
            throw new CloudRuntimeException(msg);

        }

        createdVolume = _volsDao.findById(volumeId);

        try {
            if (success) {
                createdVolume.setPodId(pod.first().getId());
                createdVolume.setPoolId(pool.getId());
                createdVolume.setPoolType(pool.getPoolType());
                createdVolume.setFolder(volumeFolder);
                createdVolume.setPath(volumeUUID);
                createdVolume.setDomainId(account.getDomainId());
                stateTransitTo(createdVolume, Volume.Event.OperationSucceeded);
            }
        } catch (NoTransitionException e) {
            s_logger.debug("Failed to update volume state: " + e.toString());
            return null;
        }

        return new Pair<VolumeVO, String>(createdVolume, details);
    }

    @Override
    public boolean stateTransitTo(Volume vol, Volume.Event event) throws NoTransitionException {
        return _volStateMachine.transitTo(vol, event, null, _volsDao);
    }

    protected VolumeVO createVolumeFromSnapshot(VolumeVO volume, long snapshotId) {

        // By default, assume failure.
        VolumeVO createdVolume = null;
        SnapshotVO snapshot = _snapshotDao.findById(snapshotId); // Precondition: snapshot is not null and not removed.

        Pair<VolumeVO, String> volumeDetails = createVolumeFromSnapshot(volume, snapshot);
        if (volumeDetails != null) {
            createdVolume = volumeDetails.first();
            UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_CREATE, createdVolume.getAccountId(),
                    createdVolume.getDataCenterId(), createdVolume.getId(), createdVolume.getName(), createdVolume.getDiskOfferingId(),
                    null, createdVolume.getSize(), Volume.class.getName(), createdVolume.getUuid());
        }
        return createdVolume;
    }

    protected Pair<String, String> createVDIFromSnapshot(long userId, SnapshotVO snapshot, StoragePoolVO pool) {
        String vdiUUID = null;
        Long snapshotId = snapshot.getId();
        Long volumeId = snapshot.getVolumeId();
        Long dcId = snapshot.getDataCenterId();
        String secondaryStoragePoolUrl = _snapMgr.getSecondaryStorageURL(snapshot);
        long accountId = snapshot.getAccountId();

        String backedUpSnapshotUuid = snapshot.getBackupSnapshotId();
        snapshot = _snapshotDao.findById(snapshotId);
        if (snapshot.getVersion().trim().equals("2.1")) {
            VolumeVO volume = _volsDao.findByIdIncludingRemoved(volumeId);
            if (volume == null) {
                throw new CloudRuntimeException("failed to upgrade snapshot " + snapshotId + " due to unable to find orignal volume:" + volumeId + ", try it later ");
            }
            if (volume.getTemplateId() == null) {
                _snapshotDao.updateSnapshotVersion(volumeId, "2.1", "2.2");
            } else {
                VMTemplateVO template = _templateDao.findByIdIncludingRemoved(volume.getTemplateId());
                if (template == null) {
                    throw new CloudRuntimeException("failed to upgrade snapshot " + snapshotId + " due to unalbe to find orignal template :" + volume.getTemplateId() + ", try it later ");
                }
                Long templateId = template.getId();
                Long tmpltAccountId = template.getAccountId();
                if (!_snapshotDao.lockInLockTable(snapshotId.toString(), 10)) {
                    throw new CloudRuntimeException("failed to upgrade snapshot " + snapshotId + " due to this snapshot is being used, try it later ");
                }
                UpgradeSnapshotCommand cmd = new UpgradeSnapshotCommand(null, secondaryStoragePoolUrl, dcId, accountId, volumeId, templateId, tmpltAccountId, null, snapshot.getBackupSnapshotId(),
                        snapshot.getName(), "2.1");
                Answer answer = null;
                try {
                    answer = sendToPool(pool, cmd);
                } catch (StorageUnavailableException e) {
                } finally {
                    _snapshotDao.unlockFromLockTable(snapshotId.toString());
                }
                if ((answer != null) && answer.getResult()) {
                    _snapshotDao.updateSnapshotVersion(volumeId, "2.1", "2.2");
                } else {
                    return new Pair<String, String>(null, "Unable to upgrade snapshot from 2.1 to 2.2 for " + snapshot.getId());
                }
            }
        }
        String basicErrMsg = "Failed to create volume from " + snapshot.getName() + " on pool " + pool;
        try {
            if (snapshot.getSwiftId() != null && snapshot.getSwiftId() != 0) {
                _snapshotMgr.downloadSnapshotsFromSwift(snapshot);
            } else if (snapshot.getS3Id() != null && snapshot.getS3Id() != 0) {
                _snapshotMgr.downloadSnapshotsFromS3(snapshot);
            }
            CreateVolumeFromSnapshotCommand createVolumeFromSnapshotCommand = new CreateVolumeFromSnapshotCommand(pool, secondaryStoragePoolUrl, dcId, accountId, volumeId,
                    backedUpSnapshotUuid, snapshot.getName(), _createVolumeFromSnapshotWait);
            CreateVolumeFromSnapshotAnswer answer;
            if (!_snapshotDao.lockInLockTable(snapshotId.toString(), 10)) {
                throw new CloudRuntimeException("failed to create volume from " + snapshotId + " due to this snapshot is being used, try it later ");
            }
            answer = (CreateVolumeFromSnapshotAnswer) sendToPool(pool, createVolumeFromSnapshotCommand);
            if (answer != null && answer.getResult()) {
                vdiUUID = answer.getVdi();
            } else {
                s_logger.error(basicErrMsg + " due to " + ((answer == null) ? "null" : answer.getDetails()));
                throw new CloudRuntimeException(basicErrMsg);
            }
        } catch (StorageUnavailableException e) {
            s_logger.error(basicErrMsg);
        } finally {
            if (snapshot.getSwiftId() != null) {
                _snapshotMgr.deleteSnapshotsDirForVolume(secondaryStoragePoolUrl, dcId, accountId, volumeId);
            }
            _snapshotDao.unlockFromLockTable(snapshotId.toString());
        }
        return new Pair<String, String>(vdiUUID, basicErrMsg);
    }


    @Override
    @DB
    public VolumeVO copyVolumeFromSecToPrimary(VolumeVO volume, VMInstanceVO vm, VMTemplateVO template, DataCenterVO dc, HostPodVO pod, Long clusterId, ServiceOfferingVO offering, DiskOfferingVO diskOffering,
            List<StoragePoolVO> avoids, long size, HypervisorType hyperType) throws NoTransitionException {

        final HashSet<StoragePool> avoidPools = new HashSet<StoragePool>(avoids);
        DiskProfile dskCh = createDiskCharacteristics(volume, template, dc, diskOffering);
        dskCh.setHyperType(vm.getHypervisorType());
        // Find a suitable storage to create volume on 
        StoragePoolVO destPool = findStoragePool(dskCh, dc, pod, clusterId, null, vm, avoidPools);

        // Copy the volume from secondary storage to the destination storage pool    	  	
        stateTransitTo(volume, Event.CopyRequested);
        VolumeHostVO volumeHostVO = _volumeHostDao.findByVolumeId(volume.getId());
        HostVO secStorage = _hostDao.findById(volumeHostVO.getHostId());
        String secondaryStorageURL = secStorage.getStorageUrl();
        String[] volumePath = volumeHostVO.getInstallPath().split("/");
        String volumeUUID = volumePath[volumePath.length - 1].split("\\.")[0];

        CopyVolumeCommand cvCmd = new CopyVolumeCommand(volume.getId(), volumeUUID, destPool, secondaryStorageURL, false, _copyvolumewait);
        CopyVolumeAnswer cvAnswer;
        try {
            cvAnswer = (CopyVolumeAnswer) sendToPool(destPool, cvCmd);
        } catch (StorageUnavailableException e1) {
            stateTransitTo(volume, Event.CopyFailed);
            throw new CloudRuntimeException("Failed to copy the volume from secondary storage to the destination primary storage pool.");
        }

        if (cvAnswer == null || !cvAnswer.getResult()) {
            stateTransitTo(volume, Event.CopyFailed);
            throw new CloudRuntimeException("Failed to copy the volume from secondary storage to the destination primary storage pool.");
        }        
        Transaction txn = Transaction.currentTxn();
        txn.start();        
        volume.setPath(cvAnswer.getVolumePath());
        volume.setFolder(destPool.getPath());
        volume.setPodId(destPool.getPodId());
        volume.setPoolId(destPool.getId());        
        volume.setPodId(destPool.getPodId());
        stateTransitTo(volume, Event.CopySucceeded); 
        UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_CREATE, volume.getAccountId(),
                volume.getDataCenterId(), volume.getId(), volume.getName(), volume.getDiskOfferingId(),
                null, volume.getSize(), Volume.class.getName(), volume.getUuid());
        _volumeHostDao.remove(volumeHostVO.getId());
        txn.commit();
        return volume;

    }

    @Override
    @DB
    public VolumeVO createVolume(VolumeVO volume, VMInstanceVO vm, VMTemplateVO template, DataCenterVO dc, HostPodVO pod, Long clusterId, ServiceOfferingVO offering, DiskOfferingVO diskOffering,
            List<StoragePoolVO> avoids, long size, HypervisorType hyperType) {
        StoragePoolVO pool = null;
        final HashSet<StoragePool> avoidPools = new HashSet<StoragePool>(avoids);

        try {
            stateTransitTo(volume, Volume.Event.CreateRequested);
        } catch (NoTransitionException e) {
            s_logger.debug("Unable to update volume state: " + e.toString());
            return null;
        }

        if (diskOffering != null && diskOffering.isCustomized()) {
            diskOffering.setDiskSize(size);
        }
        DiskProfile dskCh = null;
        if (volume.getVolumeType() == Type.ROOT && Storage.ImageFormat.ISO != template.getFormat()) {
            dskCh = createDiskCharacteristics(volume, template, dc, offering);
        } else {
            dskCh = createDiskCharacteristics(volume, template, dc, diskOffering);
        }

        dskCh.setHyperType(hyperType);

        VolumeTO created = null;
        int retry = _retry;
        while (--retry >= 0) {
            created = null;

            long podId = pod.getId();
            pod = _podDao.findById(podId);
            if (pod == null) {
                s_logger.warn("Unable to find pod " + podId + " when create volume " + volume.getName());
                break;
            }

            pool = findStoragePool(dskCh, dc, pod, clusterId, vm.getHostId(), vm, avoidPools);
            if (pool == null) {
                s_logger.warn("Unable to find storage poll when create volume " + volume.getName());
                break;
            }

            avoidPools.add(pool);
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Trying to create " + volume + " on " + pool);
            }

            CreateCommand cmd = null;
            VMTemplateStoragePoolVO tmpltStoredOn = null;

            for (int i = 0; i < 2; i++) {
                if (volume.getVolumeType() == Type.ROOT && Storage.ImageFormat.ISO != template.getFormat()) {
                    if (pool.getPoolType() == StoragePoolType.CLVM) {
                        //prepareISOForCreate does what we need, which is to tell us where the template is
                        VMTemplateHostVO tmpltHostOn = _tmpltMgr.prepareISOForCreate(template, pool);
                        if (tmpltHostOn == null) {
                            continue;
                        }
                        HostVO secondaryStorageHost = _hostDao.findById(tmpltHostOn.getHostId());
                        String tmpltHostUrl = secondaryStorageHost.getStorageUrl();
                        String fullTmpltUrl = tmpltHostUrl + "/" + tmpltHostOn.getInstallPath();
                        cmd = new CreateCommand(dskCh, fullTmpltUrl, new StorageFilerTO(pool));
                    } else {
                        tmpltStoredOn = _tmpltMgr.prepareTemplateForCreate(template, pool);
                        if (tmpltStoredOn == null) {
                            continue;
                        }
                        cmd = new CreateCommand(dskCh, tmpltStoredOn.getLocalDownloadPath(), new StorageFilerTO(pool));
                    }
                } else {
                    if (volume.getVolumeType() == Type.ROOT && Storage.ImageFormat.ISO == template.getFormat()) {
                        VMTemplateHostVO tmpltHostOn = _tmpltMgr.prepareISOForCreate(template, pool);
                        if (tmpltHostOn == null) {
                            throw new CloudRuntimeException("Did not find ISO in secondry storage in zone " + pool.getDataCenterId());
                        }
                    }
                    cmd = new CreateCommand(dskCh, new StorageFilerTO(pool));
                }

                try {
                    Answer answer = sendToPool(pool, cmd);
                    if (answer != null && answer.getResult()) {
                        created = ((CreateAnswer) answer).getVolume();
                        break;
                    }

                    if (tmpltStoredOn != null && answer != null && (answer instanceof CreateAnswer) && ((CreateAnswer) answer).templateReloadRequested()) {
                        if (!_tmpltMgr.resetTemplateDownloadStateOnPool(tmpltStoredOn.getId())) {
                            break; // break out of template-redeploy retry loop
                        }
                    } else {
                        break;
                    }
                } catch (StorageUnavailableException e) {
                    s_logger.debug("Storage unavailable for " + pool.getId());
                    break; // break out of template-redeploy retry loop
                }
            }

            if (created != null) {
                break;
            }

            s_logger.debug("Retrying the create because it failed on pool " + pool);
        }

        if (created == null) {
            return null;
        } else {
            volume.setFolder(pool.getPath());
            volume.setPath(created.getPath());
            volume.setSize(created.getSize());
            volume.setPoolType(pool.getPoolType());
            volume.setPoolId(pool.getId());
            volume.setPodId(pod.getId());
            try {
                stateTransitTo(volume, Volume.Event.OperationSucceeded);
            } catch (NoTransitionException e) {
                s_logger.debug("Unable to update volume state: " + e.toString());
                return null;
            }
            return volume;
        }
    }

    public Long chooseHostForStoragePool(StoragePoolVO poolVO, List<Long> avoidHosts, boolean sendToVmResidesOn, Long vmId) {
        if (sendToVmResidesOn) {
            if (vmId != null) {
                VMInstanceVO vmInstance = _vmInstanceDao.findById(vmId);
                if (vmInstance != null) {
                    Long hostId = vmInstance.getHostId();
                    if (hostId != null && !avoidHosts.contains(vmInstance.getHostId())) {
                        return hostId;
                    }
                }
            }
            /*
             * Can't find the vm where host resides on(vm is destroyed? or volume is detached from vm), randomly choose
             * a host
             * to send the cmd
             */
        }
        List<StoragePoolHostVO> poolHosts = _poolHostDao.listByHostStatus(poolVO.getId(), Status.Up);
        Collections.shuffle(poolHosts);
        if (poolHosts != null && poolHosts.size() > 0) {
            for (StoragePoolHostVO sphvo : poolHosts) {
                if (!avoidHosts.contains(sphvo.getHostId())) {
                    return sphvo.getHostId();
                }
            }
        }
        return null;
    }

    @Override
    public boolean configure(String name, Map<String, Object> params) throws ConfigurationException {

        Map<String, String> configs = _configDao.getConfiguration("management-server", params);

        String overProvisioningFactorStr = configs.get("storage.overprovisioning.factor");
        if (overProvisioningFactorStr != null) {
            _overProvisioningFactor = new BigDecimal(overProvisioningFactorStr);
        }

        _retry = NumbersUtil.parseInt(configs.get(Config.StartRetry.key()), 10);
        _pingInterval = NumbersUtil.parseInt(configs.get("ping.interval"), 60);
        _hostRetry = NumbersUtil.parseInt(configs.get("host.retry"), 2);
        _storagePoolAcquisitionWaitSeconds = NumbersUtil.parseInt(configs.get("pool.acquisition.wait.seconds"), 1800);
        s_logger.info("pool.acquisition.wait.seconds is configured as " + _storagePoolAcquisitionWaitSeconds + " seconds");

        _agentMgr.registerForHostEvents(new StoragePoolMonitor(this, _storagePoolDao), true, false, true);

        String storageCleanupEnabled = configs.get("storage.cleanup.enabled");
        _storageCleanupEnabled = (storageCleanupEnabled == null) ? true : Boolean.parseBoolean(storageCleanupEnabled);

        String value = _configDao.getValue(Config.CreateVolumeFromSnapshotWait.toString());
        _createVolumeFromSnapshotWait = NumbersUtil.parseInt(value, Integer.parseInt(Config.CreateVolumeFromSnapshotWait.getDefaultValue()));

        value = _configDao.getValue(Config.CopyVolumeWait.toString());
        _copyvolumewait = NumbersUtil.parseInt(value, Integer.parseInt(Config.CopyVolumeWait.getDefaultValue()));

        value = _configDao.getValue(Config.RecreateSystemVmEnabled.key());
        _recreateSystemVmEnabled = Boolean.parseBoolean(value);

        value = _configDao.getValue(Config.StorageTemplateCleanupEnabled.key());
        _templateCleanupEnabled = (value == null ? true : Boolean.parseBoolean(value));

        String time = configs.get("storage.cleanup.interval");
        _storageCleanupInterval = NumbersUtil.parseInt(time, 86400);

        String storageUsedThreshold = _configDao.getValue(Config.StorageCapacityDisableThreshold.key());
        if (storageUsedThreshold != null) {
            _storageUsedThreshold = Double.parseDouble(storageUsedThreshold);
        }

        String storageAllocatedThreshold = _configDao.getValue(Config.StorageAllocatedCapacityDisableThreshold.key());
        if (storageAllocatedThreshold != null) {
            _storageAllocatedThreshold = Double.parseDouble(storageAllocatedThreshold);
        }

        String globalStorageOverprovisioningFactor = configs.get("storage.overprovisioning.factor");
        _storageOverprovisioningFactor = new BigDecimal(NumbersUtil.parseFloat(globalStorageOverprovisioningFactor, 2.0f));

        s_logger.info("Storage cleanup enabled: " + _storageCleanupEnabled + ", interval: " + _storageCleanupInterval + ", template cleanup enabled: " + _templateCleanupEnabled);

        String workers = configs.get("expunge.workers");
        int wrks = NumbersUtil.parseInt(workers, 10);
        _executor = Executors.newScheduledThreadPool(wrks, new NamedThreadFactory("StorageManager-Scavenger"));

        _agentMgr.registerForHostEvents(ComponentContext.inject(LocalStoragePoolListener.class), true, false, false);

        String maxVolumeSizeInGbString = _configDao.getValue("storage.max.volume.size");
        _maxVolumeSizeInGb = NumbersUtil.parseLong(maxVolumeSizeInGbString, 2000);

        String _customDiskOfferingMinSizeStr = _configDao.getValue(Config.CustomDiskOfferingMinSize.toString());
        _customDiskOfferingMinSize = NumbersUtil.parseInt(_customDiskOfferingMinSizeStr, Integer.parseInt(Config.CustomDiskOfferingMinSize.getDefaultValue()));

        String _customDiskOfferingMaxSizeStr = _configDao.getValue(Config.CustomDiskOfferingMaxSize.toString());
        _customDiskOfferingMaxSize = NumbersUtil.parseInt(_customDiskOfferingMaxSizeStr, Integer.parseInt(Config.CustomDiskOfferingMaxSize.getDefaultValue()));

        HostTemplateStatesSearch = _vmTemplateHostDao.createSearchBuilder();
        HostTemplateStatesSearch.and("id", HostTemplateStatesSearch.entity().getTemplateId(), SearchCriteria.Op.EQ);
        HostTemplateStatesSearch.and("state", HostTemplateStatesSearch.entity().getDownloadState(), SearchCriteria.Op.EQ);

        SearchBuilder<HostVO> HostSearch = _hostDao.createSearchBuilder();
        HostSearch.and("dcId", HostSearch.entity().getDataCenterId(), SearchCriteria.Op.EQ);

        HostTemplateStatesSearch.join("host", HostSearch, HostSearch.entity().getId(), HostTemplateStatesSearch.entity().getHostId(), JoinBuilder.JoinType.INNER);
        HostSearch.done();
        HostTemplateStatesSearch.done();

        _serverId = _msServer.getId();

        UpHostsInPoolSearch = _storagePoolHostDao.createSearchBuilder(Long.class);
        UpHostsInPoolSearch.selectField(UpHostsInPoolSearch.entity().getHostId());
        SearchBuilder<HostVO> hostSearch = _hostDao.createSearchBuilder();
        hostSearch.and("status", hostSearch.entity().getStatus(), Op.EQ);
        hostSearch.and("resourceState", hostSearch.entity().getResourceState(), Op.EQ);
        UpHostsInPoolSearch.join("hosts", hostSearch, hostSearch.entity().getId(), UpHostsInPoolSearch.entity().getHostId(), JoinType.INNER);
        UpHostsInPoolSearch.and("pool", UpHostsInPoolSearch.entity().getPoolId(), Op.EQ);
        UpHostsInPoolSearch.done();

        StoragePoolSearch = _vmInstanceDao.createSearchBuilder();

        SearchBuilder<VolumeVO> volumeSearch = _volumeDao.createSearchBuilder();
        volumeSearch.and("volumeType", volumeSearch.entity().getVolumeType(), SearchCriteria.Op.EQ);
        volumeSearch.and("poolId", volumeSearch.entity().getPoolId(), SearchCriteria.Op.EQ);
        StoragePoolSearch.join("vmVolume", volumeSearch, volumeSearch.entity().getInstanceId(), StoragePoolSearch.entity().getId(), JoinBuilder.JoinType.INNER);
        StoragePoolSearch.done();

        LocalStorageSearch = _storagePoolDao.createSearchBuilder();
        SearchBuilder<StoragePoolHostVO> storageHostSearch = _storagePoolHostDao.createSearchBuilder();
        storageHostSearch.and("hostId", storageHostSearch.entity().getHostId(), SearchCriteria.Op.EQ);
        LocalStorageSearch.join("poolHost", storageHostSearch, storageHostSearch.entity().getPoolId(), LocalStorageSearch.entity().getId(), JoinBuilder.JoinType.INNER);
        LocalStorageSearch.and("type", LocalStorageSearch.entity().getPoolType(), SearchCriteria.Op.IN);
        LocalStorageSearch.done();

        Volume.State.getStateMachine().registerListener( new VolumeStateListener());

        return true;
    }

    public String getRandomVolumeName() {
        return UUID.randomUUID().toString();
    }

    @Override
    public boolean volumeOnSharedStoragePool(VolumeVO volume) {
        Long poolId = volume.getPoolId();
        if (poolId == null) {
            return false;
        } else {
            StoragePoolVO pool = _storagePoolDao.findById(poolId);

            if (pool == null) {
                return false;
            } else {
                return pool.isShared();
            }
        }
    }

    @Override
    public boolean volumeInactive(VolumeVO volume) {
        Long vmId = volume.getInstanceId();
        if (vmId != null) {
            UserVm vm = _userVmDao.findById(vmId);
            if (vm == null) {
                return true;
            }
            State state = vm.getState();
            if (state.equals(State.Stopped) || state.equals(State.Destroyed)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public String getVmNameOnVolume(VolumeVO volume) {
        Long vmId = volume.getInstanceId();
        if (vmId != null) {
            VMInstanceVO vm = _vmInstanceDao.findById(vmId);

            if (vm == null) {
                return null;
            }
            return vm.getInstanceName();
        }
        return null;
    }

    @Override
    public Pair<String, String> getAbsoluteIsoPath(long templateId, long dataCenterId) {
        String isoPath = null;

        List<HostVO> storageHosts = _resourceMgr.listAllHostsInOneZoneByType(Host.Type.SecondaryStorage, dataCenterId);
        if (storageHosts != null) {
            for (HostVO storageHost : storageHosts) {
                List<VMTemplateHostVO> templateHostVOs = _vmTemplateHostDao.listByTemplateHostStatus(templateId, storageHost.getId(), VMTemplateStorageResourceAssoc.Status.DOWNLOADED );
                if (templateHostVOs != null && !templateHostVOs.isEmpty()) {
                    VMTemplateHostVO tmpHostVO = templateHostVOs.get(0);
                    isoPath = storageHost.getStorageUrl() + "/" + tmpHostVO.getInstallPath();
                    return new Pair<String, String>(isoPath, storageHost.getStorageUrl());
                }
            }
        }
        s_logger.warn("Unable to find secondary storage in zone id=" + dataCenterId);
        return null;
    }

    @Override
    public String getSecondaryStorageURL(long zoneId) {
        // Determine the secondary storage URL
        HostVO secondaryStorageHost = getSecondaryStorageHost(zoneId);

        if (secondaryStorageHost == null) {
            return null;
        }

        return secondaryStorageHost.getStorageUrl();
    }

    @Override
    public HostVO getSecondaryStorageHost(long zoneId, long tmpltId) {
        List<HostVO> hosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
        if (hosts == null || hosts.size() == 0) {
            return null;
        }
        for (HostVO host : hosts) {
            VMTemplateHostVO tmpltHost = _vmTemplateHostDao.findByHostTemplate(host.getId(), tmpltId);
            if (tmpltHost != null && !tmpltHost.getDestroyed() && tmpltHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOADED) {
                return host;
            }
        }
        return null;
    }

    @Override
    public VMTemplateHostVO getTemplateHostRef(long zoneId, long tmpltId, boolean readyOnly) {
        List<HostVO> hosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
        if (hosts == null || hosts.size() == 0) {
            return null;
        }
        VMTemplateHostVO inProgress = null;
        VMTemplateHostVO other = null;
        for (HostVO host : hosts) {
            VMTemplateHostVO tmpltHost = _vmTemplateHostDao.findByHostTemplate(host.getId(), tmpltId);
            if (tmpltHost != null && !tmpltHost.getDestroyed()) {
                if (tmpltHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOADED) {
                    return tmpltHost;
                } else if (tmpltHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOAD_IN_PROGRESS) {
                    inProgress = tmpltHost;
                } else {
                    other = tmpltHost;
                }
            }
        }
        if (inProgress != null) {
            return inProgress;
        }
        return other;
    }

    @Override
    public HostVO getSecondaryStorageHost(long zoneId) {
        List<HostVO> hosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
        if (hosts == null || hosts.size() == 0) {
            hosts = _ssvmMgr.listLocalSecondaryStorageHostsInOneZone(zoneId);
            if (hosts.isEmpty()) {
                return null;
            }
        }

        int size = hosts.size();
        Random rn = new Random();
        int index = rn.nextInt(size);
        return hosts.get(index);
    }

    @Override
    public List<HostVO> getSecondaryStorageHosts(long zoneId) {
        List<HostVO> hosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
        if (hosts == null || hosts.size() == 0) {
            hosts = _ssvmMgr.listLocalSecondaryStorageHostsInOneZone(zoneId);
            if (hosts.isEmpty()) {
                return new ArrayList<HostVO>();
            }
        }
        return hosts;
    }

    @Override
    public String getStoragePoolTags(long poolId) {
        return _configMgr.listToCsvTags(_storagePoolDao.searchForStoragePoolDetails(poolId, "true"));
    }

    @Override
    public boolean start() {
        if (_storageCleanupEnabled) {
            Random generator = new Random();
            int initialDelay = generator.nextInt(_storageCleanupInterval);
            _executor.scheduleWithFixedDelay(new StorageGarbageCollector(), initialDelay, _storageCleanupInterval, TimeUnit.SECONDS);
        } else {
            s_logger.debug("Storage cleanup is not enabled, so the storage cleanup thread is not being scheduled.");
        }

        return true;
    }

    @Override
    public boolean stop() {
        if (_storageCleanupEnabled) {
            _executor.shutdown();
        }

        return true;
    }

    protected StorageManagerImpl() {
        _volStateMachine = Volume.State.getStateMachine();
    }

    @Override
    @SuppressWarnings("rawtypes")
    public StoragePoolVO createPool(CreateStoragePoolCmd cmd) throws ResourceInUseException, IllegalArgumentException, UnknownHostException, ResourceUnavailableException {
        Long clusterId = cmd.getClusterId();
        Long podId = cmd.getPodId();
        Map ds = cmd.getDetails();

        if (clusterId != null && podId == null) {
            throw new InvalidParameterValueException("Cluster id requires pod id");
        }

        Map<String, String> details = new HashMap<String, String>();
        if (ds != null) {
            Collection detailsCollection = ds.values();
            Iterator it = detailsCollection.iterator();
            while (it.hasNext()) {
                HashMap d = (HashMap) it.next();
                Iterator it2 = d.entrySet().iterator();
                while (it2.hasNext()) {
                    Map.Entry entry = (Map.Entry) it2.next();
                    details.put((String) entry.getKey(), (String) entry.getValue());
                }
            }
        }

        // verify input parameters
        Long zoneId = cmd.getZoneId();
        DataCenterVO zone = _dcDao.findById(cmd.getZoneId());
        if (zone == null) {
            throw new InvalidParameterValueException("unable to find zone by id " + zoneId);
        }
        // Check if zone is disabled
        Account account = UserContext.current().getCaller();
        if (Grouping.AllocationState.Disabled == zone.getAllocationState() && !_accountMgr.isRootAdmin(account.getType())) {
            throw new PermissionDeniedException("Cannot perform this operation, Zone is currently disabled: " + zoneId);
        }

        // Check if there is host up in this cluster
        List<HostVO> allHosts = _resourceMgr.listAllUpAndEnabledHosts(Host.Type.Routing, clusterId, podId, zoneId);
        if (allHosts.isEmpty()) {
            throw new ResourceUnavailableException("No host up to associate a storage pool with in cluster " + clusterId, Pod.class, podId);
        }
        URI uri = null;
        try {
            uri = new URI(UriUtils.encodeURIComponent(cmd.getUrl()));
            if (uri.getScheme() == null) {
                throw new InvalidParameterValueException("scheme is null " + cmd.getUrl() + ", add nfs:// as a prefix");
            } else if (uri.getScheme().equalsIgnoreCase("nfs")) {
                String uriHost = uri.getHost();
                String uriPath = uri.getPath();
                if (uriHost == null || uriPath == null || uriHost.trim().isEmpty() || uriPath.trim().isEmpty()) {
                    throw new InvalidParameterValueException("host or path is null, should be nfs://hostname/path");
                }
            } else if (uri.getScheme().equalsIgnoreCase("sharedMountPoint")) {
                String uriPath = uri.getPath();
                if (uriPath == null) {
                    throw new InvalidParameterValueException("host or path is null, should be sharedmountpoint://localhost/path");
                }
            }  else if (uri.getScheme().equalsIgnoreCase("rbd")) {
                String uriPath = uri.getPath();
                if (uriPath == null) {
                    throw new InvalidParameterValueException("host or path is null, should be rbd://hostname/pool");
                }
            }
        } catch (URISyntaxException e) {
            throw new InvalidParameterValueException(cmd.getUrl() + " is not a valid uri");
        }

        String tags = cmd.getTags();
        if (tags != null) {
            String[] tokens = tags.split(",");

            for (String tag : tokens) {
                tag = tag.trim();
                if (tag.length() == 0) {
                    continue;
                }
                details.put(tag, "true");
            }
        }

        String scheme = uri.getScheme();
        String storageHost = uri.getHost();
        String hostPath = uri.getPath();
        String userInfo = uri.getUserInfo();
        int port = uri.getPort();
        StoragePoolVO pool = null;
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("createPool Params @ scheme - " + scheme + " storageHost - " + storageHost + " hostPath - " + hostPath + " port - " + port);
        }
        if (scheme.equalsIgnoreCase("nfs")) {
            if (port == -1) {
                port = 2049;
            }
            pool = new StoragePoolVO(StoragePoolType.NetworkFilesystem, storageHost, port, hostPath);
            if (clusterId == null) {
                throw new IllegalArgumentException("NFS need to have clusters specified for XenServers");
            }
        } else if (scheme.equalsIgnoreCase("file")) {
            if (port == -1) {
                port = 0;
            }
            pool = new StoragePoolVO(StoragePoolType.Filesystem, "localhost", 0, hostPath);
        } else if (scheme.equalsIgnoreCase("sharedMountPoint")) {
            pool = new StoragePoolVO(StoragePoolType.SharedMountPoint, storageHost, 0, hostPath);
        } else if (scheme.equalsIgnoreCase("clvm")) {
            pool = new StoragePoolVO(StoragePoolType.CLVM, storageHost, 0, hostPath.replaceFirst("/", ""));
        } else if (scheme.equalsIgnoreCase("rbd")) {
            if (port == -1) {
                port = 6789;
            }
            pool = new StoragePoolVO(StoragePoolType.RBD, storageHost, port, hostPath.replaceFirst("/", ""), userInfo);
        } else if (scheme.equalsIgnoreCase("PreSetup")) {
            pool = new StoragePoolVO(StoragePoolType.PreSetup, storageHost, 0, hostPath);
        } else if (scheme.equalsIgnoreCase("iscsi")) {
            String[] tokens = hostPath.split("/");
            int lun = NumbersUtil.parseInt(tokens[tokens.length - 1], -1);
            if (port == -1) {
                port = 3260;
            }
            if (lun != -1) {
                if (clusterId == null) {
                    throw new IllegalArgumentException("IscsiLUN need to have clusters specified");
                }
                hostPath.replaceFirst("/", "");
                pool = new StoragePoolVO(StoragePoolType.IscsiLUN, storageHost, port, hostPath);
            } else {
                for (StoragePoolDiscoverer discoverer : _discoverers) {
                    Map<StoragePoolVO, Map<String, String>> pools;
                    try {
                        pools = discoverer.find(cmd.getZoneId(), podId, uri, details);
                    } catch (DiscoveryException e) {
                        throw new IllegalArgumentException("Not enough information for discovery " + uri, e);
                    }
                    if (pools != null) {
                        Map.Entry<StoragePoolVO, Map<String, String>> entry = pools.entrySet().iterator().next();
                        pool = entry.getKey();
                        details = entry.getValue();
                        break;
                    }
                }
            }
        } else if (scheme.equalsIgnoreCase("iso")) {
            if (port == -1) {
                port = 2049;
            }
            pool = new StoragePoolVO(StoragePoolType.ISO, storageHost, port, hostPath);
        } else if (scheme.equalsIgnoreCase("vmfs")) {
            pool = new StoragePoolVO(StoragePoolType.VMFS, "VMFS datastore: " + hostPath, 0, hostPath);
        } else if (scheme.equalsIgnoreCase("ocfs2")) {
            port = 7777;
            pool = new StoragePoolVO(StoragePoolType.OCFS2, "clustered", port, hostPath);
        } else {
            s_logger.warn("Unable to figure out the scheme for URI: " + uri);
            throw new IllegalArgumentException("Unable to figure out the scheme for URI: " + uri);
        }

        if (pool == null) {
            s_logger.warn("Unable to figure out the scheme for URI: " + uri);
            throw new IllegalArgumentException("Unable to figure out the scheme for URI: " + uri);
        }

        List<StoragePoolVO> pools = _storagePoolDao.listPoolByHostPath(storageHost, hostPath);
        if (!pools.isEmpty() && !scheme.equalsIgnoreCase("sharedmountpoint")) {
            Long oldPodId = pools.get(0).getPodId();
            throw new ResourceInUseException("Storage pool " + uri + " already in use by another pod (id=" + oldPodId + ")", "StoragePool", uri.toASCIIString());
        }

        long poolId = _storagePoolDao.getNextInSequence(Long.class, "id");
        String uuid = null;
        if (scheme.equalsIgnoreCase("sharedmountpoint") || scheme.equalsIgnoreCase("clvm")) {
            uuid = UUID.randomUUID().toString();
        } else if (scheme.equalsIgnoreCase("PreSetup")) {
            uuid = hostPath.replace("/", "");
        } else {
            uuid = UUID.nameUUIDFromBytes(new String(storageHost + hostPath).getBytes()).toString();
        }

        List<StoragePoolVO> spHandles = _storagePoolDao.findIfDuplicatePoolsExistByUUID(uuid);
        if ((spHandles != null) && (spHandles.size() > 0)) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Another active pool with the same uuid already exists");
            }
            throw new ResourceInUseException("Another active pool with the same uuid already exists");
        }

        if (s_logger.isDebugEnabled()) {
            s_logger.debug("In createPool Setting poolId - " + poolId + " uuid - " + uuid + " zoneId - " + zoneId + " podId - " + podId + " poolName - " + cmd.getStoragePoolName());
        }

        pool.setId(poolId);
        pool.setUuid(uuid);
        pool.setDataCenterId(cmd.getZoneId());
        pool.setPodId(podId);
        pool.setName(cmd.getStoragePoolName());
        pool.setClusterId(clusterId);
        pool.setStatus(StoragePoolStatus.Up);
        pool = _storagePoolDao.persist(pool, details);

        if (pool.getPoolType() == StoragePoolType.OCFS2 && !_ocfs2Mgr.prepareNodes(allHosts, pool)) {
            s_logger.warn("Can not create storage pool " + pool + " on cluster " + clusterId);
            _storagePoolDao.expunge(pool.getId());
            return null;
        }

        boolean success = false;
        for (HostVO h : allHosts) {
            success = createStoragePool(h.getId(), pool);
            if (success) {
                break;
            }
        }
        if (!success) {
            s_logger.warn("Can not create storage pool " + pool + " on cluster " + clusterId);
            _storagePoolDao.expunge(pool.getId());
            return null;
        }
        s_logger.debug("In createPool Adding the pool to each of the hosts");
        List<HostVO> poolHosts = new ArrayList<HostVO>();
        for (HostVO h : allHosts) {
            try {
                connectHostToSharedPool(h.getId(), pool);
                poolHosts.add(h);
            } catch (Exception e) {
                s_logger.warn("Unable to establish a connection between " + h + " and " + pool, e);
            }
        }

        if (poolHosts.isEmpty()) {
            s_logger.warn("No host can access storage pool " + pool + " on cluster " + clusterId);
            _storagePoolDao.expunge(pool.getId());
            return null;
        } else {
            createCapacityEntry(pool);
        }
        return pool;
    }

    @Override
    public StoragePoolVO updateStoragePool(UpdateStoragePoolCmd cmd) throws IllegalArgumentException {
        // Input validation
        Long id = cmd.getId();
        List<String> tags = cmd.getTags();

        StoragePoolVO pool = _storagePoolDao.findById(id);
        if (pool == null) {
            throw new IllegalArgumentException("Unable to find storage pool with ID: " + id);
        }

        if (tags != null) {
            Map<String, String> details = new HashMap<String, String>();
            for (String tag : tags) {
                tag = tag.trim();
                if (tag.length() > 0 && !details.containsKey(tag)) {
                    details.put(tag, "true");
                }
            }

            _storagePoolDao.updateDetails(id, details);
        }

        return pool;
    }

    @Override
    @DB
    public boolean deletePool(DeletePoolCmd cmd) {
        Long id = cmd.getId();
        boolean deleteFlag = false;
        boolean forced = cmd.isForced();

        // verify parameters
        StoragePoolVO sPool = _storagePoolDao.findById(id);
        if (sPool == null) {
            s_logger.warn("Unable to find pool:" + id);
            throw new InvalidParameterValueException("Unable to find pool by id " + id);
        }
        if(sPool.getStatus() != StoragePoolStatus.Maintenance){
            s_logger.warn("Unable to delete storage id: " + id +" due to it is not in Maintenance state");
            throw new InvalidParameterValueException("Unable to delete storage due to it is not in Maintenance state, id: " + id);           
        }
        if (sPool.getPoolType().equals(StoragePoolType.LVM) || sPool.getPoolType().equals(StoragePoolType.EXT)) {
            s_logger.warn("Unable to delete local storage id:" + id);
            throw new InvalidParameterValueException("Unable to delete local storage id: " + id);
        }

        Pair<Long, Long> vlms = _volsDao.getCountAndTotalByPool(id);
        if (forced) {
            if (vlms.first() > 0) {
                Pair<Long, Long> nonDstrdVlms = _volsDao.getNonDestroyedCountAndTotalByPool(id);
                if (nonDstrdVlms.first() > 0) {
                    throw new CloudRuntimeException("Cannot delete pool " + sPool.getName() + " as there are associated " +
                            "non-destroyed vols for this pool");
                }
                //force expunge non-destroyed volumes
                List<VolumeVO> vols = _volsDao.listVolumesToBeDestroyed();
                for (VolumeVO vol : vols) {
                    expungeVolume(vol, true);
                }
            }
        } else {
            // Check if the pool has associated volumes in the volumes table
            // If it does , then you cannot delete the pool
            if (vlms.first() > 0) {
                throw new CloudRuntimeException("Cannot delete pool " + sPool.getName() + " as there are associated vols" +
                        " for this pool");
            }
        }


        // First get the host_id from storage_pool_host_ref for given pool id
        StoragePoolVO lock = _storagePoolDao.acquireInLockTable(sPool.getId());

        if (lock == null) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Failed to acquire lock when deleting StoragePool with ID: " + sPool.getId());
            }
            return false;
        }

        // mark storage pool as removed (so it can't be used for new volumes creation), release the lock
        boolean isLockReleased = false;
        isLockReleased = _storagePoolDao.releaseFromLockTable(lock.getId());
        s_logger.trace("Released lock for storage pool " + id);

        // for the given pool id, find all records in the storage_pool_host_ref
        List<StoragePoolHostVO> hostPoolRecords = _storagePoolHostDao.listByPoolId(id);
        Transaction txn = Transaction.currentTxn();
        try {
            // if not records exist, delete the given pool (base case)
            if (hostPoolRecords.size() == 0) {

                txn.start();
                sPool.setUuid(null);
                _storagePoolDao.update(id, sPool);
                _storagePoolDao.remove(id);
                deletePoolStats(id);
                txn.commit();

                deleteFlag = true;
                return true;
            } else {
                // Remove the SR associated with the Xenserver
                for (StoragePoolHostVO host : hostPoolRecords) {
                    DeleteStoragePoolCommand deleteCmd = new DeleteStoragePoolCommand(sPool);
                    final Answer answer = _agentMgr.easySend(host.getHostId(), deleteCmd);

                    if (answer != null && answer.getResult()) {
                        deleteFlag = true;
                        break;
                    }
                }
            }
        } finally {
            if (deleteFlag) {
                // now delete the storage_pool_host_ref and storage_pool records
                txn.start();
                for (StoragePoolHostVO host : hostPoolRecords) {
                    _storagePoolHostDao.deleteStoragePoolHostDetails(host.getHostId(), host.getPoolId());
                }
                sPool.setUuid(null);
                _storagePoolDao.update(id, sPool);
                _storagePoolDao.remove(id);
                deletePoolStats(id);
                // Delete op_host_capacity entries
                _capacityDao.removeBy(Capacity.CAPACITY_TYPE_STORAGE_ALLOCATED, null, null, null, id);
                txn.commit();

                s_logger.debug("Storage pool id=" + id + " is removed successfully");
                return true;
            } else {
                // alert that the storage cleanup is required
                s_logger.warn("Failed to Delete storage pool id: " + id);
                _alertMgr.sendAlert(AlertManager.ALERT_TYPE_STORAGE_DELETE, sPool.getDataCenterId(), sPool.getPodId(), "Unable to delete storage pool id= " + id,
                        "Delete storage pool command failed.  Please check logs.");
            }

            if (lock != null && !isLockReleased) {
                _storagePoolDao.releaseFromLockTable(lock.getId());
            }
        }

        return false;

    }

    @DB
    private boolean deletePoolStats(Long poolId) {
        CapacityVO capacity1 = _capacityDao.findByHostIdType(poolId, CapacityVO.CAPACITY_TYPE_STORAGE);
        CapacityVO capacity2 = _capacityDao.findByHostIdType(poolId, CapacityVO.CAPACITY_TYPE_STORAGE_ALLOCATED);
        Transaction txn = Transaction.currentTxn();
        txn.start();
        if (capacity1 != null) {
            _capacityDao.remove(capacity1.getId());
        }

        if (capacity2 != null) {
            _capacityDao.remove(capacity2.getId());
        }

        txn.commit();
        return true;

    }

    @Override
    public boolean createStoragePool(long hostId, StoragePoolVO pool) {
        s_logger.debug("creating pool " + pool.getName() + " on  host " + hostId);
        if (pool.getPoolType() != StoragePoolType.NetworkFilesystem && pool.getPoolType() != StoragePoolType.Filesystem && pool.getPoolType() != StoragePoolType.IscsiLUN
                && pool.getPoolType() != StoragePoolType.Iscsi && pool.getPoolType() != StoragePoolType.VMFS && pool.getPoolType() != StoragePoolType.SharedMountPoint
                && pool.getPoolType() != StoragePoolType.PreSetup && pool.getPoolType() != StoragePoolType.OCFS2 && pool.getPoolType() != StoragePoolType.RBD && pool.getPoolType() != StoragePoolType.CLVM) {
            s_logger.warn(" Doesn't support storage pool type " + pool.getPoolType());
            return false;
        }
        CreateStoragePoolCommand cmd = new CreateStoragePoolCommand(true, pool);
        final Answer answer = _agentMgr.easySend(hostId, cmd);
        if (answer != null && answer.getResult()) {
            return true;
        } else {
            _storagePoolDao.expunge(pool.getId());
            String msg = "";
            if (answer != null) {
                msg = "Can not create storage pool through host " + hostId + " due to " + answer.getDetails();
                s_logger.warn(msg);
            } else {
                msg = "Can not create storage pool through host " + hostId + " due to CreateStoragePoolCommand returns null";
                s_logger.warn(msg);
            }
            throw new CloudRuntimeException(msg);
        }
    }

    @Override
    public boolean delPoolFromHost(long hostId) {
        List<StoragePoolHostVO> poolHosts = _poolHostDao.listByHostIdIncludingRemoved(hostId);
        for (StoragePoolHostVO poolHost : poolHosts) {
            s_logger.debug("Deleting pool " + poolHost.getPoolId() + " from  host " + hostId);
            _poolHostDao.remove(poolHost.getId());
        }
        return true;
    }

    public void connectHostToSharedPool(long hostId, StoragePoolVO pool) throws StorageUnavailableException {
        assert (pool.getPoolType().isShared()) : "Now, did you actually read the name of this method?";
        s_logger.debug("Adding pool " + pool.getName() + " to  host " + hostId);

        ModifyStoragePoolCommand cmd = new ModifyStoragePoolCommand(true, pool);
        final Answer answer = _agentMgr.easySend(hostId, cmd);

        if (answer == null) {
            throw new StorageUnavailableException("Unable to get an answer to the modify storage pool command", pool.getId());
        }

        if (!answer.getResult()) {
            String msg = "Add host failed due to ModifyStoragePoolCommand failed" + answer.getDetails();
            _alertMgr.sendAlert(AlertManager.ALERT_TYPE_HOST, pool.getDataCenterId(), pool.getPodId(), msg, msg);
            throw new StorageUnavailableException("Unable establish connection from storage head to storage pool " + pool.getId() + " due to " + answer.getDetails(), pool.getId());
        }

        assert (answer instanceof ModifyStoragePoolAnswer) : "Well, now why won't you actually return the ModifyStoragePoolAnswer when it's ModifyStoragePoolCommand? Pool=" + pool.getId() + "Host=" + hostId;
        ModifyStoragePoolAnswer mspAnswer = (ModifyStoragePoolAnswer) answer;

        StoragePoolHostVO poolHost = _poolHostDao.findByPoolHost(pool.getId(), hostId);
        if (poolHost == null) {
            poolHost = new StoragePoolHostVO(pool.getId(), hostId, mspAnswer.getPoolInfo().getLocalPath().replaceAll("//", "/"));
            _poolHostDao.persist(poolHost);
        } else {
            poolHost.setLocalPath(mspAnswer.getPoolInfo().getLocalPath().replaceAll("//", "/"));
        }
        pool.setAvailableBytes(mspAnswer.getPoolInfo().getAvailableBytes());
        pool.setCapacityBytes(mspAnswer.getPoolInfo().getCapacityBytes());
        _storagePoolDao.update(pool.getId(), pool);

        s_logger.info("Connection established between " + pool + " host + " + hostId);
    }

    @Override
    public VolumeVO moveVolume(VolumeVO volume, long destPoolDcId, Long destPoolPodId, Long destPoolClusterId, HypervisorType dataDiskHyperType) throws ConcurrentOperationException {

        // Find a destination storage pool with the specified criteria
        DiskOfferingVO diskOffering = _diskOfferingDao.findById(volume.getDiskOfferingId());
        DiskProfile dskCh = new DiskProfile(volume.getId(), volume.getVolumeType(), volume.getName(), diskOffering.getId(), diskOffering.getDiskSize(), diskOffering.getTagsArray(),
                diskOffering.getUseLocalStorage(), diskOffering.isRecreatable(), null);
        dskCh.setHyperType(dataDiskHyperType);
        DataCenterVO destPoolDataCenter = _dcDao.findById(destPoolDcId);
        HostPodVO destPoolPod = _podDao.findById(destPoolPodId);
        StoragePoolVO destPool = findStoragePool(dskCh, destPoolDataCenter, destPoolPod, destPoolClusterId, null, null, new HashSet<StoragePool>());
        String secondaryStorageURL = getSecondaryStorageURL(volume.getDataCenterId());

        if (destPool == null) {
            throw new CloudRuntimeException("Failed to find a storage pool with enough capacity to move the volume to.");
        }
        if (secondaryStorageURL == null) {
            throw new CloudRuntimeException("Failed to find secondary storage.");
        }

        List<Volume> vols = new ArrayList<Volume>();
        vols.add(volume);
        migrateVolumes(vols, destPool);
        return _volsDao.findById(volume.getId());
    }


    /*
     * Upload the volume to secondary storage.
     * 
     */
    @Override
    @DB
    @ActionEvent(eventType = EventTypes.EVENT_VOLUME_UPLOAD, eventDescription = "uploading volume", async = true)
    public VolumeVO uploadVolume(UploadVolumeCmd cmd) throws ResourceAllocationException{
        Account caller = UserContext.current().getCaller();
        long ownerId = cmd.getEntityOwnerId();
        Long zoneId = cmd.getZoneId();
        String volumeName = cmd.getVolumeName();
        String url = cmd.getUrl();
        String format = cmd.getFormat();

        validateVolume(caller, ownerId, zoneId, volumeName, url, format);
        VolumeVO volume = persistVolume(caller, ownerId, zoneId, volumeName, url, cmd.getFormat());
        _downloadMonitor.downloadVolumeToStorage(volume, zoneId, url, cmd.getChecksum(), ImageFormat.valueOf(format.toUpperCase()));
        return volume;    	
    }

    private boolean validateVolume(Account caller, long ownerId, Long zoneId, String volumeName, String url, String format) throws ResourceAllocationException{

        // permission check
        _accountMgr.checkAccess(caller, null, true, _accountMgr.getActiveAccountById(ownerId));

        // Check that the resource limit for volumes won't be exceeded
        _resourceLimitMgr.checkResourceLimit(_accountMgr.getAccount(ownerId), ResourceType.volume);


        // Verify that zone exists
        DataCenterVO zone = _dcDao.findById(zoneId);
        if (zone == null) {
            throw new InvalidParameterValueException("Unable to find zone by id " + zoneId);
        }

        // Check if zone is disabled
        if (Grouping.AllocationState.Disabled == zone.getAllocationState() && !_accountMgr.isRootAdmin(caller.getType())) {
            throw new PermissionDeniedException("Cannot perform this operation, Zone is currently disabled: " + zoneId);
        }

        if (url.toLowerCase().contains("file://")) {
            throw new InvalidParameterValueException("File:// type urls are currently unsupported");
        }

        ImageFormat imgfmt = ImageFormat.valueOf(format.toUpperCase());
        if (imgfmt == null) {
            throw new IllegalArgumentException("Image format is incorrect " + format + ". Supported formats are " + EnumUtils.listValues(ImageFormat.values()));
        }

        String userSpecifiedName = volumeName;
        if (userSpecifiedName == null) {
            userSpecifiedName = getRandomVolumeName();
        }
        if((!url.toLowerCase().endsWith("vhd"))&&(!url.toLowerCase().endsWith("vhd.zip"))
                &&(!url.toLowerCase().endsWith("vhd.bz2"))&&(!url.toLowerCase().endsWith("vhd.gz")) 
                &&(!url.toLowerCase().endsWith("qcow2"))&&(!url.toLowerCase().endsWith("qcow2.zip"))
                &&(!url.toLowerCase().endsWith("qcow2.bz2"))&&(!url.toLowerCase().endsWith("qcow2.gz"))
                &&(!url.toLowerCase().endsWith("ova"))&&(!url.toLowerCase().endsWith("ova.zip"))
                &&(!url.toLowerCase().endsWith("ova.bz2"))&&(!url.toLowerCase().endsWith("ova.gz"))
                &&(!url.toLowerCase().endsWith("img"))&&(!url.toLowerCase().endsWith("raw"))){
            throw new InvalidParameterValueException("Please specify a valid " + format.toLowerCase());
        }

        if ((format.equalsIgnoreCase("vhd") && (!url.toLowerCase().endsWith(".vhd") && !url.toLowerCase().endsWith("vhd.zip") && !url.toLowerCase().endsWith("vhd.bz2") && !url.toLowerCase().endsWith("vhd.gz") ))
                || (format.equalsIgnoreCase("qcow2") && (!url.toLowerCase().endsWith(".qcow2") && !url.toLowerCase().endsWith("qcow2.zip") && !url.toLowerCase().endsWith("qcow2.bz2") && !url.toLowerCase().endsWith("qcow2.gz") ))
                || (format.equalsIgnoreCase("ova") && (!url.toLowerCase().endsWith(".ova") && !url.toLowerCase().endsWith("ova.zip") && !url.toLowerCase().endsWith("ova.bz2") && !url.toLowerCase().endsWith("ova.gz")))
                || (format.equalsIgnoreCase("raw") && (!url.toLowerCase().endsWith(".img") && !url.toLowerCase().endsWith("raw")))) {
            throw new InvalidParameterValueException("Please specify a valid URL. URL:" + url + " is an invalid for the format " + format.toLowerCase());
        }
        validateUrl(url);

        return false;
    }

    private String validateUrl(String url){
        try {
            URI uri = new URI(url);
            if ((uri.getScheme() == null) || (!uri.getScheme().equalsIgnoreCase("http") 
                    && !uri.getScheme().equalsIgnoreCase("https") && !uri.getScheme().equalsIgnoreCase("file"))) {
                throw new IllegalArgumentException("Unsupported scheme for url: " + url);
            }

            int port = uri.getPort();
            if (!(port == 80 || port == 443 || port == -1)) {
                throw new IllegalArgumentException("Only ports 80 and 443 are allowed");
            }
            String host = uri.getHost();
            try {
                InetAddress hostAddr = InetAddress.getByName(host);
                if (hostAddr.isAnyLocalAddress() || hostAddr.isLinkLocalAddress() || hostAddr.isLoopbackAddress() || hostAddr.isMulticastAddress()) {
                    throw new IllegalArgumentException("Illegal host specified in url");
                }
                if (hostAddr instanceof Inet6Address) {
                    throw new IllegalArgumentException("IPV6 addresses not supported (" + hostAddr.getHostAddress() + ")");
                }
            } catch (UnknownHostException uhe) {
                throw new IllegalArgumentException("Unable to resolve " + host);
            }

            return uri.toString();
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException("Invalid URL " + url);
        }

    }

    private VolumeVO persistVolume(Account caller, long ownerId, Long zoneId, String volumeName, String url, String format) {

        Transaction txn = Transaction.currentTxn();
        txn.start();

        VolumeVO volume = new VolumeVO(volumeName, zoneId, -1, -1, -1, new Long(-1), null, null, 0, Volume.Type.DATADISK);
        volume.setPoolId(null);
        volume.setDataCenterId(zoneId);
        volume.setPodId(null);
        volume.setAccountId(ownerId);
        volume.setDomainId(((caller == null) ? Domain.ROOT_DOMAIN : caller.getDomainId()));
        long diskOfferingId = _diskOfferingDao.findByUniqueName("Cloud.com-Custom").getId();
        volume.setDiskOfferingId(diskOfferingId);        
        //volume.setSize(size);
        volume.setInstanceId(null);
        volume.setUpdated(new Date());
        volume.setDomainId((caller == null) ? Domain.ROOT_DOMAIN : caller.getDomainId());

        volume = _volsDao.persist(volume);
        try {
            stateTransitTo(volume, Event.UploadRequested);
        } catch (NoTransitionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        UserContext.current().setEventDetails("Volume Id: " + volume.getId());

        // Increment resource count during allocation; if actual creation fails, decrement it
        _resourceLimitMgr.incrementResourceCount(volume.getAccountId(), ResourceType.volume);

        txn.commit();
        return volume;
    }


    /*
     * Just allocate a volume in the database, don't send the createvolume cmd to hypervisor. The volume will be finally
     * created
     * only when it's attached to a VM.
     */
    @Override
    @DB
    @ActionEvent(eventType = EventTypes.EVENT_VOLUME_CREATE, eventDescription = "creating volume", create = true)
    public VolumeVO allocVolume(CreateVolumeCmd cmd) throws ResourceAllocationException {
        // FIXME: some of the scheduled event stuff might be missing here...
        Account caller = UserContext.current().getCaller();

        long ownerId = cmd.getEntityOwnerId();

        // permission check
        _accountMgr.checkAccess(caller, null, true, _accountMgr.getActiveAccountById(ownerId));

        // Check that the resource limit for volumes won't be exceeded
        _resourceLimitMgr.checkResourceLimit(_accountMgr.getAccount(ownerId), ResourceType.volume);

        Long zoneId = cmd.getZoneId();
        Long diskOfferingId = null;
        DiskOfferingVO diskOffering = null;
        Long size = null;

        // validate input parameters before creating the volume
        if ((cmd.getSnapshotId() == null && cmd.getDiskOfferingId() == null) || (cmd.getSnapshotId() != null && cmd.getDiskOfferingId() != null)) {
            throw new InvalidParameterValueException("Either disk Offering Id or snapshot Id must be passed whilst creating volume");
        }

        if (cmd.getSnapshotId() == null) {// create a new volume

            diskOfferingId = cmd.getDiskOfferingId();
            size = cmd.getSize();
            Long sizeInGB = size;
            if (size != null) {
                if (size > 0) {
                    size = size * 1024 * 1024 * 1024; // user specify size in GB
                } else {
                    throw new InvalidParameterValueException("Disk size must be larger than 0");
                }
            }

            // Check that the the disk offering is specified
            diskOffering = _diskOfferingDao.findById(diskOfferingId);
            if ((diskOffering == null) || diskOffering.getRemoved() != null || !DiskOfferingVO.Type.Disk.equals(diskOffering.getType())) {
                throw new InvalidParameterValueException("Please specify a valid disk offering.");
            }

            if (diskOffering.isCustomized()) {
                if (size == null) {
                    throw new InvalidParameterValueException("This disk offering requires a custom size specified");
                }
                if ((sizeInGB < _customDiskOfferingMinSize) || (sizeInGB > _customDiskOfferingMaxSize)) {
                    throw new InvalidParameterValueException("Volume size: " + sizeInGB + "GB is out of allowed range. Max: " + _customDiskOfferingMaxSize + " Min:" + _customDiskOfferingMinSize);
                }
            }

            if (!diskOffering.isCustomized() && size != null) {
                throw new InvalidParameterValueException("This disk offering does not allow custom size");
            }

            if (diskOffering.getDomainId() == null) {
                // do nothing as offering is public
            } else {
                _configMgr.checkDiskOfferingAccess(caller, diskOffering);
            }

            if (diskOffering.getDiskSize() > 0) {
                size = diskOffering.getDiskSize();
            }

            if (!validateVolumeSizeRange(size)) {// convert size from mb to gb for validation
                throw new InvalidParameterValueException("Invalid size for custom volume creation: " + size + " ,max volume size is:" + _maxVolumeSizeInGb);
            }
        } else { // create volume from snapshot
            Long snapshotId = cmd.getSnapshotId();
            SnapshotVO snapshotCheck = _snapshotDao.findById(snapshotId);
            if (snapshotCheck == null) {
                throw new InvalidParameterValueException("unable to find a snapshot with id " + snapshotId);
            }

            if (snapshotCheck.getState() != Snapshot.State.BackedUp) {
                throw new InvalidParameterValueException("Snapshot id=" + snapshotId + " is not in " + Snapshot.State.BackedUp + " state yet and can't be used for volume creation");
            }

            diskOfferingId = snapshotCheck.getDiskOfferingId();
            diskOffering = _diskOfferingDao.findById(diskOfferingId);
            zoneId = snapshotCheck.getDataCenterId();
            size = snapshotCheck.getSize(); // ; disk offering is used for tags purposes

            // check snapshot permissions
            _accountMgr.checkAccess(caller, null, true, snapshotCheck);

            /*
             * // bug #11428. Operation not supported if vmware and snapshots parent volume = ROOT
             * if(snapshotCheck.getHypervisorType() == HypervisorType.VMware
             * && _volumeDao.findByIdIncludingRemoved(snapshotCheck.getVolumeId()).getVolumeType() == Type.ROOT){
             * throw new UnsupportedServiceException("operation not supported, snapshot with id " + snapshotId +
             * " is created from ROOT volume");
             * }
             * 
             */
        }

        // Verify that zone exists
        DataCenterVO zone = _dcDao.findById(zoneId);
        if (zone == null) {
            throw new InvalidParameterValueException("Unable to find zone by id " + zoneId);
        }

        // Check if zone is disabled
        if (Grouping.AllocationState.Disabled == zone.getAllocationState() && !_accountMgr.isRootAdmin(caller.getType())) {
            throw new PermissionDeniedException("Cannot perform this operation, Zone is currently disabled: " + zoneId);
        }

        // If local storage is disabled then creation of volume with local disk offering not allowed
        if (!zone.isLocalStorageEnabled() && diskOffering.getUseLocalStorage()) {
            throw new InvalidParameterValueException("Zone is not configured to use local storage but volume's disk offering " + diskOffering.getName() + " uses it");
        }

        // Check that there is appropriate primary storage pool in the specified zone
        List<StoragePoolVO> storagePools = _storagePoolDao.listByDataCenterId(zoneId);
        boolean appropriatePoolExists = false;
        if (!diskOffering.getUseLocalStorage()) {
            for (StoragePoolVO storagePool : storagePools) {
                if (storagePool.isShared()) {
                    appropriatePoolExists = true;
                    break;
                }
            }
        } else {
            for (StoragePoolVO storagePool : storagePools) {
                if (storagePool.isLocal()) {
                    appropriatePoolExists = true;
                    break;
                }
            }
        }

        // Check that there is at least one host in the specified zone
        List<HostVO> hosts = _resourceMgr.listAllUpAndEnabledHostsInOneZoneByType(Host.Type.Routing, zoneId);
        if (hosts.isEmpty()) {
            throw new InvalidParameterValueException("There is no workable host in data center id " + zoneId + ", please check hosts' agent status and see if they are disabled");
        }

        if (!appropriatePoolExists) {
            String storageType = diskOffering.getUseLocalStorage() ? ServiceOffering.StorageType.local.toString() : ServiceOffering.StorageType.shared.toString();
            throw new InvalidParameterValueException("Volume's disk offering uses " + storageType + " storage, please specify a zone that has at least one " + storageType + " primary storage pool.");
        }

        String userSpecifiedName = cmd.getVolumeName();
        if (userSpecifiedName == null) {
            userSpecifiedName = getRandomVolumeName();
        }

        Transaction txn = Transaction.currentTxn();
        txn.start();

        VolumeVO volume = new VolumeVO(userSpecifiedName, -1, -1, -1, -1, new Long(-1), null, null, 0, Volume.Type.DATADISK);
        volume.setPoolId(null);
        volume.setDataCenterId(zoneId);
        volume.setPodId(null);
        volume.setAccountId(ownerId);
        volume.setDomainId(((caller == null) ? Domain.ROOT_DOMAIN : caller.getDomainId()));
        volume.setDiskOfferingId(diskOfferingId);
        volume.setSize(size);
        volume.setInstanceId(null);
        volume.setUpdated(new Date());
        volume.setDomainId((caller == null) ? Domain.ROOT_DOMAIN : caller.getDomainId());

        volume = _volsDao.persist(volume);
        if(cmd.getSnapshotId() == null){
            //for volume created from snapshot, create usage event after volume creation
            UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_CREATE, volume.getAccountId(),
                    volume.getDataCenterId(), volume.getId(), volume.getName(), diskOfferingId, null, size,
                    Volume.class.getName(), volume.getUuid());
        }

        UserContext.current().setEventDetails("Volume Id: " + volume.getId());

        // Increment resource count during allocation; if actual creation fails, decrement it
        _resourceLimitMgr.incrementResourceCount(volume.getAccountId(), ResourceType.volume);

        txn.commit();

        return volume;
    }

    @Override
    @DB
    @ActionEvent(eventType = EventTypes.EVENT_VOLUME_CREATE, eventDescription = "creating volume", async = true)
    public VolumeVO createVolume(CreateVolumeCmd cmd) {
        VolumeVO volume = _volsDao.findById(cmd.getEntityId());
        boolean created = false;

        try {
            if (cmd.getSnapshotId() != null) {
                volume = createVolumeFromSnapshot(volume, cmd.getSnapshotId());
                if (volume.getState() == Volume.State.Ready) {
                    created = true;
                }
                return volume;
            } else {
                _volsDao.update(volume.getId(), volume);
                created = true;
            }

            return _volsDao.findById(volume.getId());
        } finally {
            if (!created) {
                s_logger.trace("Decrementing volume resource count for account id=" + volume.getAccountId() + " as volume failed to create on the backend");
                _resourceLimitMgr.decrementResourceCount(volume.getAccountId(), ResourceType.volume);
            }
        }
    }

    @Override
    @DB
    @ActionEvent(eventType = EventTypes.EVENT_VOLUME_RESIZE, eventDescription = "resizing volume", async = true)
    public VolumeVO resizeVolume(ResizeVolumeCmd cmd) {
        VolumeVO volume = _volsDao.findById(cmd.getEntityId());
        Long newSize = null;
        boolean shrinkOk = cmd.getShrinkOk();
        boolean success = false;
        DiskOfferingVO diskOffering = _diskOfferingDao.findById(volume.getDiskOfferingId());
        DiskOfferingVO newDiskOffering = null;

        newDiskOffering = _diskOfferingDao.findById(cmd.getNewDiskOfferingId());

        /* Volumes with no hypervisor have never been assigned, and can be resized by recreating.
           perhaps in the future we can just update the db entry for the volume */
        if(_volsDao.getHypervisorType(volume.getId()) == HypervisorType.None){
            throw new InvalidParameterValueException("Can't resize a volume that has never been attached, not sure which hypervisor type. Recreate volume to resize.");
        }

        /* Only works for KVM/Xen for now */
        if(_volsDao.getHypervisorType(volume.getId()) != HypervisorType.KVM 
           && _volsDao.getHypervisorType(volume.getId()) != HypervisorType.XenServer){
            throw new InvalidParameterValueException("Cloudstack currently only supports volumes marked as KVM or XenServer hypervisor for resize");
        }

        if (volume == null) {
            throw new InvalidParameterValueException("No such volume");
        }

        if (volume.getState() != Volume.State.Ready) {
            throw new InvalidParameterValueException("Volume should be in ready state before attempting a resize");
        }

        if (!volume.getVolumeType().equals(Volume.Type.DATADISK)) {
            throw new InvalidParameterValueException("Can only resize DATA volumes");
        }

        /* figure out whether or not a new disk offering or size parameter is required, get the correct size value */
        if (newDiskOffering == null) {
            if (diskOffering.isCustomized()) {
                newSize = cmd.getSize();

                if (newSize == null) {
                    throw new InvalidParameterValueException("new offering is of custom size, need to specify a size");
                }

                newSize = ( newSize << 30 );
            } else {
                throw new InvalidParameterValueException("current offering" + volume.getDiskOfferingId()  + " cannot be resized, need to specify a disk offering");
            }
        } else {

            if (newDiskOffering.getRemoved() != null || !DiskOfferingVO.Type.Disk.equals(newDiskOffering.getType())) {
                throw new InvalidParameterValueException("Disk offering ID is missing or invalid");
            }

            if(diskOffering.getTags() != null) {
                if(!newDiskOffering.getTags().equals(diskOffering.getTags())){
                    throw new InvalidParameterValueException("Tags on new and old disk offerings must match");
                }
            } else if (newDiskOffering.getTags() != null ){
                throw new InvalidParameterValueException("There are no tags on current disk offering, new disk offering needs to have no tags");
            }

            if (newDiskOffering.getDomainId() == null) {
                // do nothing as offering is public
            } else {
                _configMgr.checkDiskOfferingAccess(UserContext.current().getCaller(), newDiskOffering);
            }
 
            if (newDiskOffering.isCustomized()) {
                newSize = cmd.getSize();

                if (newSize == null) {
                    throw new InvalidParameterValueException("new offering is of custom size, need to specify a size");
                }

                newSize = ( newSize << 30 );
            } else {
                newSize = newDiskOffering.getDiskSize();
            }
        }

        if (newSize == null) {
            throw new InvalidParameterValueException("could not detect a size parameter or fetch one from the diskofferingid parameter");
        }

        if (!validateVolumeSizeRange(newSize)) {
            throw new InvalidParameterValueException("Requested size out of range");
        }

        /* does the caller have the authority to act on this volume? */
        _accountMgr.checkAccess(UserContext.current().getCaller(), null, true, volume);

        UserVmVO userVm = _userVmDao.findById(volume.getInstanceId());

        StoragePool pool = _storagePoolDao.findById(volume.getPoolId());
        long currentSize = volume.getSize();

        /* lets make certain they (think they) know what they're doing if they 
        want to shrink, by forcing them to provide the shrinkok parameter. This will
        be checked again at the hypervisor level where we can see the actual disk size */
        if (currentSize > newSize && !shrinkOk) {
            throw new InvalidParameterValueException("Going from existing size of " + currentSize + " to size of " 
                      + newSize + " would shrink the volume, need to sign off by supplying the shrinkok parameter with value of true");
        }

        /* get a list of hosts to send the commands to, try the system the 
        associated vm is running on first, then the last known place it ran.
        If not attached to a userVm, we pass 'none' and resizevolume.sh is
        ok with that since it only needs the vm name to live resize */
        long[] hosts = null;
        String instanceName = "none";
        if (userVm != null) {
            instanceName = userVm.getInstanceName();
            if(userVm.getHostId() != null) {
                hosts = new long[] { userVm.getHostId() };
            } else if(userVm.getLastHostId() != null) {
                hosts = new long[] { userVm.getLastHostId() };
            }

            /*Xen only works offline, SR does not support VDI.resizeOnline*/
            if(_volsDao.getHypervisorType(volume.getId()) == HypervisorType.XenServer
               && ! userVm.getState().equals(State.Stopped)) {
                throw new InvalidParameterValueException("VM must be stopped or disk detached in order to resize with the Xen HV");
            }
        }

        try {
            try {
                    stateTransitTo(volume, Volume.Event.ResizeRequested);
            } catch (NoTransitionException etrans) {
                    throw new CloudRuntimeException("Unable to change volume state for resize: " + etrans.toString());
            }

            ResizeVolumeCommand resizeCmd = new ResizeVolumeCommand(volume.getPath(), new StorageFilerTO(pool), 
                                                    currentSize, newSize, shrinkOk, instanceName);
            ResizeVolumeAnswer answer = (ResizeVolumeAnswer) sendToPool(pool, hosts, resizeCmd);

            /* need to fetch/store new volume size in database. This value comes from 
            hypervisor rather than trusting that a success means we have a volume of the 
            size we requested */
            if (answer != null && answer.getResult()) {
                long finalSize = answer.getNewSize();
                s_logger.debug("Resize: volume started at size " + currentSize + " and ended at size " + finalSize);
                volume.setSize(finalSize);
                if (newDiskOffering != null) {
                    volume.setDiskOfferingId(cmd.getNewDiskOfferingId());
                }
                _volsDao.update(volume.getId(), volume);

                success  = true;
                return volume;
            } else if (answer != null) {
                s_logger.debug("Resize: returned '" + answer.getDetails() + "'");
            }
        } catch (StorageUnavailableException e) {
            s_logger.debug("volume failed to resize: "+e);
            return null;
        } finally {
            if(success) {
                try {
                    stateTransitTo(volume, Volume.Event.OperationSucceeded);
                } catch (NoTransitionException etrans) {
                    throw new CloudRuntimeException("Failed to change volume state: " + etrans.toString());
                }
            } else {
                try {
                    stateTransitTo(volume, Volume.Event.OperationFailed);
                } catch (NoTransitionException etrans) {
                    throw new CloudRuntimeException("Failed to change volume state: " + etrans.toString());
                }
            } 
        }
        return null;
    }

    @Override
    @DB
    public boolean destroyVolume(VolumeVO volume) throws ConcurrentOperationException {
        try {
            if (!stateTransitTo(volume, Volume.Event.DestroyRequested)) {
                throw new ConcurrentOperationException("Failed to transit to destroyed state");
            }
        } catch (NoTransitionException e) {
            s_logger.debug("Unable to destoy the volume: " + e.toString());
            return false;
        }

        long volumeId = volume.getId();

        // Delete the recurring snapshot policies for this volume.
        _snapshotMgr.deletePoliciesForVolume(volumeId);

        Long instanceId = volume.getInstanceId();
        VMInstanceVO vmInstance = null;
        if (instanceId != null) {
            vmInstance = _vmInstanceDao.findById(instanceId);
        }

        if (instanceId == null || (vmInstance.getType().equals(VirtualMachine.Type.User))) {
            // Decrement the resource count for volumes belonging user VM's only
            _resourceLimitMgr.decrementResourceCount(volume.getAccountId(), ResourceType.volume);
            // Log usage event for volumes belonging user VM's only
            UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_DELETE, volume.getAccountId(),
                    volume.getDataCenterId(), volume.getId(), volume.getName(),
                    Volume.class.getName(), volume.getUuid());
        }

        try {
            if (!stateTransitTo(volume, Volume.Event.OperationSucceeded)) {
                throw new ConcurrentOperationException("Failed to transit state");

            }
        } catch (NoTransitionException e) {
            s_logger.debug("Unable to change volume state: " + e.toString());
            return false;
        }

        return true;

    }

    @Override
    public void createCapacityEntry(StoragePoolVO storagePool) {
        createCapacityEntry(storagePool, Capacity.CAPACITY_TYPE_STORAGE_ALLOCATED, 0);
    }

    @Override
    public void createCapacityEntry(StoragePoolVO storagePool, short capacityType, long allocated) {
        SearchCriteria<CapacityVO> capacitySC = _capacityDao.createSearchCriteria();
        capacitySC.addAnd("hostOrPoolId", SearchCriteria.Op.EQ, storagePool.getId());
        capacitySC.addAnd("dataCenterId", SearchCriteria.Op.EQ, storagePool.getDataCenterId());
        capacitySC.addAnd("capacityType", SearchCriteria.Op.EQ, capacityType);

        List<CapacityVO> capacities = _capacityDao.search(capacitySC, null);

        long totalOverProvCapacity;
        if (storagePool.getPoolType() == StoragePoolType.NetworkFilesystem) {
            totalOverProvCapacity = _overProvisioningFactor.multiply(new BigDecimal(storagePool.getCapacityBytes())).longValue();// All this for the inaccuracy of floats for big number multiplication.
        } else {
            totalOverProvCapacity = storagePool.getCapacityBytes();
        }

        if (capacities.size() == 0) {
            CapacityVO capacity = new CapacityVO(storagePool.getId(), storagePool.getDataCenterId(), storagePool.getPodId(), storagePool.getClusterId(), allocated, totalOverProvCapacity, capacityType);
            CapacityState capacityState = _configMgr.findClusterAllocationState(ApiDBUtils.findClusterById(storagePool.getClusterId())) == AllocationState.Disabled ?
                    CapacityState.Disabled : CapacityState.Enabled;
            capacity.setCapacityState(capacityState);
            _capacityDao.persist(capacity);
        } else {
            CapacityVO capacity = capacities.get(0);
            boolean update = false;
            if (capacity.getTotalCapacity() != totalOverProvCapacity) {
                capacity.setTotalCapacity(totalOverProvCapacity);
                update = true;
            }
            if (allocated != 0) {
                capacity.setUsedCapacity(allocated);
                update = true;
            }
            if (update) {
                _capacityDao.update(capacity.getId(), capacity);
            }
        }
        s_logger.debug("Successfully set Capacity - " + totalOverProvCapacity + " for capacity type - " + capacityType + " , DataCenterId - "
                + storagePool.getDataCenterId() + ", HostOrPoolId - " + storagePool.getId() + ", PodId " + storagePool.getPodId());
    }

    @Override
    public List<Long> getUpHostsInPool(long poolId) {
        SearchCriteria<Long> sc = UpHostsInPoolSearch.create();
        sc.setParameters("pool", poolId);
        sc.setJoinParameters("hosts", "status", Status.Up);
        sc.setJoinParameters("hosts", "resourceState", ResourceState.Enabled);
        return _storagePoolHostDao.customSearch(sc, null);
    }

    @Override
    public Pair<Long, Answer[]> sendToPool(StoragePool pool, long[] hostIdsToTryFirst, List<Long> hostIdsToAvoid, Commands cmds) throws StorageUnavailableException {
        List<Long> hostIds = getUpHostsInPool(pool.getId());
        Collections.shuffle(hostIds);
        if (hostIdsToTryFirst != null) {
            for (int i = hostIdsToTryFirst.length - 1; i >= 0; i--) {
                if (hostIds.remove(hostIdsToTryFirst[i])) {
                    hostIds.add(0, hostIdsToTryFirst[i]);
                }
            }
        }

        if (hostIdsToAvoid != null) {
            hostIds.removeAll(hostIdsToAvoid);
        }
        if (hostIds == null || hostIds.isEmpty()) {
            throw new StorageUnavailableException("Unable to send command to the pool " + pool.getId() + " due to there is no enabled hosts up in this cluster", pool.getId());
        }
        for (Long hostId : hostIds) {
            try {
                List<Answer> answers = new ArrayList<Answer>();
                Command[] cmdArray = cmds.toCommands();
                for (Command cmd : cmdArray) {
                    long targetHostId = _hvGuruMgr.getGuruProcessedCommandTargetHost(hostId, cmd);

                    answers.add(_agentMgr.send(targetHostId, cmd));
                }
                return new Pair<Long, Answer[]>(hostId, answers.toArray(new Answer[answers.size()]));
            } catch (AgentUnavailableException e) {
                s_logger.debug("Unable to send storage pool command to " + pool + " via " + hostId, e);
            } catch (OperationTimedoutException e) {
                s_logger.debug("Unable to send storage pool command to " + pool + " via " + hostId, e);
            }
        }

        throw new StorageUnavailableException("Unable to send command to the pool ", pool.getId());
    }

    @Override
    public Pair<Long, Answer> sendToPool(StoragePool pool, long[] hostIdsToTryFirst, List<Long> hostIdsToAvoid, Command cmd) throws StorageUnavailableException {
        Commands cmds = new Commands(cmd);
        Pair<Long, Answer[]> result = sendToPool(pool, hostIdsToTryFirst, hostIdsToAvoid, cmds);
        return new Pair<Long, Answer>(result.first(), result.second()[0]);
    }

    @Override
    public void cleanupStorage(boolean recurring) {
        GlobalLock scanLock = GlobalLock.getInternLock("storagemgr.cleanup");

        try {
            if (scanLock.lock(3)) {
                try {
                    // Cleanup primary storage pools
                    if (_templateCleanupEnabled) {
                        List<StoragePoolVO> storagePools = _storagePoolDao.listAll();
                        for (StoragePoolVO pool : storagePools) {
                            try {

                                List<VMTemplateStoragePoolVO> unusedTemplatesInPool = _tmpltMgr.getUnusedTemplatesInPool(pool);
                                s_logger.debug("Storage pool garbage collector found " + unusedTemplatesInPool.size() + " templates to clean up in storage pool: " + pool.getName());
                                for (VMTemplateStoragePoolVO templatePoolVO : unusedTemplatesInPool) {
                                    if (templatePoolVO.getDownloadState() != VMTemplateStorageResourceAssoc.Status.DOWNLOADED) {
                                        s_logger.debug("Storage pool garbage collector is skipping templatePoolVO with ID: " + templatePoolVO.getId() + " because it is not completely downloaded.");
                                        continue;
                                    }

                                    if (!templatePoolVO.getMarkedForGC()) {
                                        templatePoolVO.setMarkedForGC(true);
                                        _vmTemplatePoolDao.update(templatePoolVO.getId(), templatePoolVO);
                                        s_logger.debug("Storage pool garbage collector has marked templatePoolVO with ID: " + templatePoolVO.getId() + " for garbage collection.");
                                        continue;
                                    }

                                    _tmpltMgr.evictTemplateFromStoragePool(templatePoolVO);
                                }
                            } catch (Exception e) {
                                s_logger.warn("Problem cleaning up primary storage pool " + pool, e);
                            }
                        }
                    }

                    cleanupSecondaryStorage(recurring);

                    List<VolumeVO> vols = _volsDao.listVolumesToBeDestroyed();
                    for (VolumeVO vol : vols) {
                        try {
                            expungeVolume(vol, false);
                        } catch (Exception e) {
                            s_logger.warn("Unable to destroy " + vol.getId(), e);
                        }
                    }

                    // remove snapshots in Error state
                    List<SnapshotVO> snapshots = _snapshotDao.listAllByStatus(Snapshot.State.Error);
                    for (SnapshotVO snapshotVO : snapshots) {
                        try{
                            _snapshotDao.expunge(snapshotVO.getId());
                        }catch (Exception e) {
                            s_logger.warn("Unable to destroy " + snapshotVO.getId(), e);
                        }
                    }

                } finally {
                    scanLock.unlock();
                }
            }
        } finally {
            scanLock.releaseRef();
        }
    }

    @DB
    List<Long> findAllVolumeIdInSnapshotTable(Long hostId) {
        String sql = "SELECT volume_id from snapshots WHERE sechost_id=? GROUP BY volume_id";
        List<Long> list = new ArrayList<Long>();
        try {
            Transaction txn = Transaction.currentTxn();
            ResultSet rs = null;
            PreparedStatement pstmt = null;
            pstmt = txn.prepareAutoCloseStatement(sql);
            pstmt.setLong(1, hostId);
            rs = pstmt.executeQuery();
            while (rs.next()) {
                list.add(rs.getLong(1));
            }
            return list;
        } catch (Exception e) {
            s_logger.debug("failed to get all volumes who has snapshots in secondary storage " + hostId + " due to " + e.getMessage());
            return null;
        }

    }

    List<String> findAllSnapshotForVolume(Long volumeId) {
        String sql = "SELECT backup_snap_id FROM snapshots WHERE volume_id=? and backup_snap_id is not NULL";
        try {
            Transaction txn = Transaction.currentTxn();
            ResultSet rs = null;
            PreparedStatement pstmt = null;
            pstmt = txn.prepareAutoCloseStatement(sql);
            pstmt.setLong(1, volumeId);
            rs = pstmt.executeQuery();
            List<String> list = new ArrayList<String>();
            while (rs.next()) {
                list.add(rs.getString(1));
            }
            return list;
        } catch (Exception e) {
            s_logger.debug("failed to get all snapshots for a volume " + volumeId + " due to " + e.getMessage());
            return null;
        }
    }

    @Override
    @DB
    public void cleanupSecondaryStorage(boolean recurring) {
        try {
            // Cleanup templates in secondary storage hosts
            List<HostVO> secondaryStorageHosts = _ssvmMgr.listSecondaryStorageHostsInAllZones();
            for (HostVO secondaryStorageHost : secondaryStorageHosts) {
                try {
                    long hostId = secondaryStorageHost.getId();
                    List<VMTemplateHostVO> destroyedTemplateHostVOs = _vmTemplateHostDao.listDestroyed(hostId);
                    s_logger.debug("Secondary storage garbage collector found " + destroyedTemplateHostVOs.size() + " templates to cleanup on secondary storage host: "
                            + secondaryStorageHost.getName());
                    for (VMTemplateHostVO destroyedTemplateHostVO : destroyedTemplateHostVOs) {
                        if (!_tmpltMgr.templateIsDeleteable(destroyedTemplateHostVO)) {
                            if (s_logger.isDebugEnabled()) {
                                s_logger.debug("Not deleting template at: " + destroyedTemplateHostVO);
                            }
                            continue;
                        }

                        if (s_logger.isDebugEnabled()) {
                            s_logger.debug("Deleting template host: " + destroyedTemplateHostVO);
                        }

                        String installPath = destroyedTemplateHostVO.getInstallPath();

                        if (installPath != null) {
                            Answer answer = _agentMgr.sendToSecStorage(secondaryStorageHost, new DeleteTemplateCommand(secondaryStorageHost.getStorageUrl(), destroyedTemplateHostVO.getInstallPath()));

                            if (answer == null || !answer.getResult()) {
                                s_logger.debug("Failed to delete " + destroyedTemplateHostVO + " due to " + ((answer == null) ? "answer is null" : answer.getDetails()));
                            } else {
                                _vmTemplateHostDao.remove(destroyedTemplateHostVO.getId());
                                s_logger.debug("Deleted template at: " + destroyedTemplateHostVO.getInstallPath());
                            }
                        } else {
                            _vmTemplateHostDao.remove(destroyedTemplateHostVO.getId());
                        }
                    }
                } catch (Exception e) {
                    s_logger.warn("problem cleaning up templates in secondary storage " + secondaryStorageHost, e);
                }
            }

            // Cleanup snapshot in secondary storage hosts
            for (HostVO secondaryStorageHost : secondaryStorageHosts) {
                try {
                    long hostId = secondaryStorageHost.getId();
                    List<Long> vIDs = findAllVolumeIdInSnapshotTable(hostId);
                    if (vIDs == null) {
                        continue;
                    }
                    for (Long volumeId : vIDs) {
                        boolean lock = false;
                        try {
                            VolumeVO volume = _volsDao.findByIdIncludingRemoved(volumeId);
                            if (volume.getRemoved() == null) {
                                volume = _volsDao.acquireInLockTable(volumeId, 10);
                                if (volume == null) {
                                    continue;
                                }
                                lock = true;
                            }
                            List<String> snapshots = findAllSnapshotForVolume(volumeId);
                            if (snapshots == null) {
                                continue;
                            }
                            CleanupSnapshotBackupCommand cmd = new CleanupSnapshotBackupCommand(secondaryStorageHost.getStorageUrl(), secondaryStorageHost.getDataCenterId(), volume.getAccountId(),
                                    volumeId, snapshots);

                            Answer answer = _agentMgr.sendToSecStorage(secondaryStorageHost, cmd);
                            if ((answer == null) || !answer.getResult()) {
                                String details = "Failed to cleanup snapshots for volume " + volumeId + " due to " + (answer == null ? "null" : answer.getDetails());
                                s_logger.warn(details);
                            }
                        } catch (Exception e1) {
                            s_logger.warn("problem cleaning up snapshots in secondary storage " + secondaryStorageHost, e1);
                        } finally {
                            if (lock) {
                                _volsDao.releaseFromLockTable(volumeId);
                            }
                        }
                    }
                } catch (Exception e2) {
                    s_logger.warn("problem cleaning up snapshots in secondary storage " + secondaryStorageHost, e2);
                }
            }

            //CleanUp volumes on Secondary Storage.
            for (HostVO secondaryStorageHost : secondaryStorageHosts) {
                try {
                    long hostId = secondaryStorageHost.getId();
                    List<VolumeHostVO> destroyedVolumeHostVOs = _volumeHostDao.listDestroyed(hostId);
                    s_logger.debug("Secondary storage garbage collector found " + destroyedVolumeHostVOs.size() + " templates to cleanup on secondary storage host: "
                            + secondaryStorageHost.getName());
                    for (VolumeHostVO destroyedVolumeHostVO : destroyedVolumeHostVOs) {
                        if (s_logger.isDebugEnabled()) {
                            s_logger.debug("Deleting volume host: " + destroyedVolumeHostVO);
                        }

                        String installPath = destroyedVolumeHostVO.getInstallPath();

                        if (installPath != null) {
                            Answer answer = _agentMgr.sendToSecStorage(secondaryStorageHost, new DeleteVolumeCommand(secondaryStorageHost.getStorageUrl(), destroyedVolumeHostVO.getInstallPath()));

                            if (answer == null || !answer.getResult()) {
                                s_logger.debug("Failed to delete " + destroyedVolumeHostVO + " due to " + ((answer == null) ? "answer is null" : answer.getDetails()));
                            } else {
                                _volumeHostDao.remove(destroyedVolumeHostVO.getId());
                                s_logger.debug("Deleted volume at: " + destroyedVolumeHostVO.getInstallPath());
                            }
                        } else {
                            _volumeHostDao.remove(destroyedVolumeHostVO.getId());
                        }
                    }

                }catch (Exception e2) {
                    s_logger.warn("problem cleaning up volumes in secondary storage " + secondaryStorageHost, e2);
                }
            }
        } catch (Exception e3) {
            s_logger.warn("problem cleaning up secondary storage ", e3);
        }
    }

    @Override
    public String getPrimaryStorageNameLabel(VolumeVO volume) {
        Long poolId = volume.getPoolId();

        // poolId is null only if volume is destroyed, which has been checked before.
        assert poolId != null;
        StoragePoolVO storagePoolVO = _storagePoolDao.findById(poolId);
        assert storagePoolVO != null;
        return storagePoolVO.getUuid();
    }

    @Override
    @DB
    public StoragePoolVO preparePrimaryStorageForMaintenance(Long primaryStorageId) throws ResourceUnavailableException, InsufficientCapacityException {
        Long userId = UserContext.current().getCallerUserId();
        User user = _userDao.findById(userId);
        Account account = UserContext.current().getCaller();
        boolean restart = true;
        StoragePoolVO primaryStorage = null;
        try {
            // 1. Get the primary storage record and perform validation check
            primaryStorage = _storagePoolDao.lockRow(primaryStorageId, true);

            if (primaryStorage == null) {
                String msg = "Unable to obtain lock on the storage pool record in preparePrimaryStorageForMaintenance()";
                s_logger.error(msg);
                throw new ExecutionException(msg);
            }

            List<StoragePoolVO> spes = _storagePoolDao.listBy(primaryStorage.getDataCenterId(), primaryStorage.getPodId(), primaryStorage.getClusterId());
            for (StoragePoolVO sp : spes) {
                if (sp.getStatus() == StoragePoolStatus.PrepareForMaintenance) {
                    throw new CloudRuntimeException("Only one storage pool in a cluster can be in PrepareForMaintenance mode, " + sp.getId() + " is already in  PrepareForMaintenance mode ");
                }
            }

            if (!primaryStorage.getStatus().equals(StoragePoolStatus.Up) && !primaryStorage.getStatus().equals(StoragePoolStatus.ErrorInMaintenance)) {
                throw new InvalidParameterValueException("Primary storage with id " + primaryStorageId + " is not ready for migration, as the status is:" + primaryStorage.getStatus().toString());
            }

            List<HostVO> hosts = _resourceMgr.listHostsInClusterByStatus(primaryStorage.getClusterId(), Status.Up);
            if (hosts == null || hosts.size() == 0) {
                primaryStorage.setStatus(StoragePoolStatus.Maintenance);
                _storagePoolDao.update(primaryStorageId, primaryStorage);
                return _storagePoolDao.findById(primaryStorageId);
            } else {
                // set the pool state to prepare for maintenance
                primaryStorage.setStatus(StoragePoolStatus.PrepareForMaintenance);
                _storagePoolDao.update(primaryStorageId, primaryStorage);
            }
            // remove heartbeat
            for (HostVO host : hosts) {
                ModifyStoragePoolCommand cmd = new ModifyStoragePoolCommand(false, primaryStorage);
                final Answer answer = _agentMgr.easySend(host.getId(), cmd);
                if (answer == null || !answer.getResult()) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("ModifyStoragePool false failed due to " + ((answer == null) ? "answer null" : answer.getDetails()));
                    }
                } else {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("ModifyStoragePool false secceeded");
                    }
                }
            }
            // check to see if other ps exist
            // if they do, then we can migrate over the system vms to them
            // if they dont, then just stop all vms on this one
            List<StoragePoolVO> upPools = _storagePoolDao.listByStatusInZone(primaryStorage.getDataCenterId(), StoragePoolStatus.Up);

            if (upPools == null || upPools.size() == 0) {
                restart = false;
            }

            // 2. Get a list of all the ROOT volumes within this storage pool
            List<VolumeVO> allVolumes = _volsDao.findByPoolId(primaryStorageId);

            // 3. Enqueue to the work queue
            for (VolumeVO volume : allVolumes) {
                VMInstanceVO vmInstance = _vmInstanceDao.findById(volume.getInstanceId());

                if (vmInstance == null) {
                    continue;
                }

                // enqueue sp work
                if (vmInstance.getState().equals(State.Running) || vmInstance.getState().equals(State.Starting) || vmInstance.getState().equals(State.Stopping)) {

                    try {
                        StoragePoolWorkVO work = new StoragePoolWorkVO(vmInstance.getId(), primaryStorageId, false, false, _serverId);
                        _storagePoolWorkDao.persist(work);
                    } catch (Exception e) {
                        if (s_logger.isDebugEnabled()) {
                            s_logger.debug("Work record already exists, re-using by re-setting values");
                        }
                        StoragePoolWorkVO work = _storagePoolWorkDao.findByPoolIdAndVmId(primaryStorageId, vmInstance.getId());
                        work.setStartedAfterMaintenance(false);
                        work.setStoppedForMaintenance(false);
                        work.setManagementServerId(_serverId);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }
                }
            }

            // 4. Process the queue
            List<StoragePoolWorkVO> pendingWork = _storagePoolWorkDao.listPendingWorkForPrepareForMaintenanceByPoolId(primaryStorageId);

            for (StoragePoolWorkVO work : pendingWork) {
                // shut down the running vms
                VMInstanceVO vmInstance = _vmInstanceDao.findById(work.getVmId());

                if (vmInstance == null) {
                    continue;
                }

                // if the instance is of type consoleproxy, call the console proxy
                if (vmInstance.getType().equals(VirtualMachine.Type.ConsoleProxy)) {
                    // call the consoleproxymanager
                    ConsoleProxyVO consoleProxy = _consoleProxyDao.findById(vmInstance.getId());
                    if (!_vmMgr.advanceStop(consoleProxy, true, user, account)) {
                        String errorMsg = "There was an error stopping the console proxy id: " + vmInstance.getId() + " ,cannot enable storage maintenance";
                        s_logger.warn(errorMsg);
                        throw new CloudRuntimeException(errorMsg);
                    } else {
                        // update work status
                        work.setStoppedForMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }

                    if (restart) {

                        if (_vmMgr.advanceStart(consoleProxy, null, user, account) == null) {
                            String errorMsg = "There was an error starting the console proxy id: " + vmInstance.getId() + " on another storage pool, cannot enable primary storage maintenance";
                            s_logger.warn(errorMsg);
                        } else {
                            // update work status
                            work.setStartedAfterMaintenance(true);
                            _storagePoolWorkDao.update(work.getId(), work);
                        }
                    }
                }

                // if the instance is of type uservm, call the user vm manager
                if (vmInstance.getType().equals(VirtualMachine.Type.User)) {
                    UserVmVO userVm = _userVmDao.findById(vmInstance.getId());
                    if (!_vmMgr.advanceStop(userVm, true, user, account)) {
                        String errorMsg = "There was an error stopping the user vm id: " + vmInstance.getId() + " ,cannot enable storage maintenance";
                        s_logger.warn(errorMsg);
                        throw new CloudRuntimeException(errorMsg);
                    } else {
                        // update work status
                        work.setStoppedForMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }
                }

                // if the instance is of type secondary storage vm, call the secondary storage vm manager
                if (vmInstance.getType().equals(VirtualMachine.Type.SecondaryStorageVm)) {
                    SecondaryStorageVmVO secStrgVm = _secStrgDao.findById(vmInstance.getId());
                    if (!_vmMgr.advanceStop(secStrgVm, true, user, account)) {
                        String errorMsg = "There was an error stopping the ssvm id: " + vmInstance.getId() + " ,cannot enable storage maintenance";
                        s_logger.warn(errorMsg);
                        throw new CloudRuntimeException(errorMsg);
                    } else {
                        // update work status
                        work.setStoppedForMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }

                    if (restart) {
                        if (_vmMgr.advanceStart(secStrgVm, null, user, account) == null) {
                            String errorMsg = "There was an error starting the ssvm id: " + vmInstance.getId() + " on another storage pool, cannot enable primary storage maintenance";
                            s_logger.warn(errorMsg);
                        } else {
                            // update work status
                            work.setStartedAfterMaintenance(true);
                            _storagePoolWorkDao.update(work.getId(), work);
                        }
                    }
                }

                // if the instance is of type domain router vm, call the network manager
                if (vmInstance.getType().equals(VirtualMachine.Type.DomainRouter)) {
                    DomainRouterVO domR = _domrDao.findById(vmInstance.getId());
                    if (!_vmMgr.advanceStop(domR, true, user, account)) {
                        String errorMsg = "There was an error stopping the domain router id: " + vmInstance.getId() + " ,cannot enable primary storage maintenance";
                        s_logger.warn(errorMsg);
                        throw new CloudRuntimeException(errorMsg);
                    } else {
                        // update work status
                        work.setStoppedForMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }

                    if (restart) {
                        if (_vmMgr.advanceStart(domR, null, user, account) == null) {
                            String errorMsg = "There was an error starting the domain router id: " + vmInstance.getId() + " on another storage pool, cannot enable primary storage maintenance";
                            s_logger.warn(errorMsg);
                        } else {
                            // update work status
                            work.setStartedAfterMaintenance(true);
                            _storagePoolWorkDao.update(work.getId(), work);
                        }
                    }
                }
            }

            // 5. Update the status
            primaryStorage.setStatus(StoragePoolStatus.Maintenance);
            _storagePoolDao.update(primaryStorageId, primaryStorage);

            return _storagePoolDao.findById(primaryStorageId);
        } catch (Exception e) {
            if (e instanceof ExecutionException || e instanceof ResourceUnavailableException) {
                s_logger.error("Exception in enabling primary storage maintenance:", e);
                setPoolStateToError(primaryStorage);
                throw (ResourceUnavailableException) e;
            }
            if (e instanceof InvalidParameterValueException) {
                s_logger.error("Exception in enabling primary storage maintenance:", e);
                setPoolStateToError(primaryStorage);
                throw (InvalidParameterValueException) e;
            }
            if (e instanceof InsufficientCapacityException) {
                s_logger.error("Exception in enabling primary storage maintenance:", e);
                setPoolStateToError(primaryStorage);
                throw (InsufficientCapacityException) e;
            }
            // for everything else
            s_logger.error("Exception in enabling primary storage maintenance:", e);
            setPoolStateToError(primaryStorage);
            throw new CloudRuntimeException(e.getMessage());

        }
    }

    private void setPoolStateToError(StoragePoolVO primaryStorage) {
        primaryStorage.setStatus(StoragePoolStatus.ErrorInMaintenance);
        _storagePoolDao.update(primaryStorage.getId(), primaryStorage);
    }

    @Override
    @DB
    public StoragePoolVO cancelPrimaryStorageForMaintenance(CancelPrimaryStorageMaintenanceCmd cmd) throws ResourceUnavailableException {
        Long primaryStorageId = cmd.getId();
        Long userId = UserContext.current().getCallerUserId();
        User user = _userDao.findById(userId);
        Account account = UserContext.current().getCaller();
        StoragePoolVO primaryStorage = null;
        try {
            Transaction txn = Transaction.currentTxn();
            txn.start();
            // 1. Get the primary storage record and perform validation check
            primaryStorage = _storagePoolDao.lockRow(primaryStorageId, true);

            if (primaryStorage == null) {
                String msg = "Unable to obtain lock on the storage pool in cancelPrimaryStorageForMaintenance()";
                s_logger.error(msg);
                throw new ExecutionException(msg);
            }

            if (primaryStorage.getStatus().equals(StoragePoolStatus.Up) || primaryStorage.getStatus().equals(StoragePoolStatus.PrepareForMaintenance)) {
                throw new StorageUnavailableException("Primary storage with id " + primaryStorageId + " is not ready to complete migration, as the status is:" + primaryStorage.getStatus().toString(),
                        primaryStorageId);
            }

            // Change the storage state back to up
            primaryStorage.setStatus(StoragePoolStatus.Up);
            _storagePoolDao.update(primaryStorageId, primaryStorage);
            txn.commit();
            List<HostVO> hosts = _resourceMgr.listHostsInClusterByStatus(primaryStorage.getClusterId(), Status.Up);
            if (hosts == null || hosts.size() == 0) {
                return _storagePoolDao.findById(primaryStorageId);
            }
            // add heartbeat
            for (HostVO host : hosts) {
                ModifyStoragePoolCommand msPoolCmd = new ModifyStoragePoolCommand(true, primaryStorage);
                final Answer answer = _agentMgr.easySend(host.getId(), msPoolCmd);
                if (answer == null || !answer.getResult()) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("ModifyStoragePool add failed due to " + ((answer == null) ? "answer null" : answer.getDetails()));
                    }
                } else {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("ModifyStoragePool add secceeded");
                    }
                }
            }

            // 2. Get a list of pending work for this queue
            List<StoragePoolWorkVO> pendingWork = _storagePoolWorkDao.listPendingWorkForCancelMaintenanceByPoolId(primaryStorageId);

            // 3. work through the queue
            for (StoragePoolWorkVO work : pendingWork) {

                VMInstanceVO vmInstance = _vmInstanceDao.findById(work.getVmId());

                if (vmInstance == null) {
                    continue;
                }

                // if the instance is of type consoleproxy, call the console proxy
                if (vmInstance.getType().equals(VirtualMachine.Type.ConsoleProxy)) {

                    ConsoleProxyVO consoleProxy = _consoleProxyDao.findById(vmInstance.getId());
                    if (_vmMgr.advanceStart(consoleProxy, null, user, account) == null) {
                        String msg = "There was an error starting the console proxy id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg);
                        throw new ExecutionException(msg);
                    } else {
                        // update work queue
                        work.setStartedAfterMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }
                }

                // if the instance is of type ssvm, call the ssvm manager
                if (vmInstance.getType().equals(VirtualMachine.Type.SecondaryStorageVm)) {
                    SecondaryStorageVmVO ssVm = _secStrgDao.findById(vmInstance.getId());
                    if (_vmMgr.advanceStart(ssVm, null, user, account) == null) {
                        String msg = "There was an error starting the ssvm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg);
                        throw new ExecutionException(msg);
                    } else {
                        // update work queue
                        work.setStartedAfterMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }
                }

                // if the instance is of type ssvm, call the ssvm manager
                if (vmInstance.getType().equals(VirtualMachine.Type.DomainRouter)) {
                    DomainRouterVO domR = _domrDao.findById(vmInstance.getId());
                    if (_vmMgr.advanceStart(domR, null, user, account) == null) {
                        String msg = "There was an error starting the domR id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg);
                        throw new ExecutionException(msg);
                    } else {
                        // update work queue
                        work.setStartedAfterMaintenance(true);
                        _storagePoolWorkDao.update(work.getId(), work);
                    }
                }

                // if the instance is of type user vm, call the user vm manager
                if (vmInstance.getType().equals(VirtualMachine.Type.User)) {
                    UserVmVO userVm = _userVmDao.findById(vmInstance.getId());
                    try {
                        if (_vmMgr.advanceStart(userVm, null, user, account) == null) {

                            String msg = "There was an error starting the user vm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                            s_logger.warn(msg);
                            throw new ExecutionException(msg);
                        } else {
                            // update work queue
                            work.setStartedAfterMaintenance(true);
                            _storagePoolWorkDao.update(work.getId(), work);
                        }
                    } catch (StorageUnavailableException e) {
                        String msg = "There was an error starting the user vm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg, e);
                        throw new ExecutionException(msg);
                    } catch (InsufficientCapacityException e) {
                        String msg = "There was an error starting the user vm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg, e);
                        throw new ExecutionException(msg);
                    } catch (ConcurrentOperationException e) {
                        String msg = "There was an error starting the user vm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg, e);
                        throw new ExecutionException(msg);
                    } catch (ExecutionException e) {
                        String msg = "There was an error starting the user vm id: " + vmInstance.getId() + " on storage pool, cannot complete primary storage maintenance";
                        s_logger.warn(msg, e);
                        throw new ExecutionException(msg);
                    }
                }
            }
            return primaryStorage;
        } catch (Exception e) {
            setPoolStateToError(primaryStorage);
            if (e instanceof ExecutionException) {
                throw (ResourceUnavailableException) e;
            } else if (e instanceof InvalidParameterValueException) {
                throw (InvalidParameterValueException) e;
            } else {// all other exceptions
                throw new CloudRuntimeException(e.getMessage());
            }
        }
    }

    private boolean sendToVmResidesOn(StoragePoolVO storagePool, Command cmd) {
        ClusterVO cluster = _clusterDao.findById(storagePool.getClusterId());
        if ((cluster.getHypervisorType() == HypervisorType.KVM || cluster.getHypervisorType() == HypervisorType.VMware)
                && ((cmd instanceof ManageSnapshotCommand) || (cmd instanceof BackupSnapshotCommand))) {
            return true;
        } else {
            return false;
        }
    }

    @Override
    @DB
    @ActionEvent(eventType = EventTypes.EVENT_VOLUME_DELETE, eventDescription = "deleting volume")
    public boolean deleteVolume(long volumeId, Account caller) throws ConcurrentOperationException {

        // Check that the volume ID is valid
        VolumeVO volume = _volsDao.findById(volumeId);
        if (volume == null) {
            throw new InvalidParameterValueException("Unable to aquire volume with ID: " + volumeId);
        }

        if (!_snapshotMgr.canOperateOnVolume(volume)) {
            throw new InvalidParameterValueException("There are snapshot creating on it, Unable to delete the volume");
        }

        // permission check
        _accountMgr.checkAccess(caller, null, true, volume);

        // Check that the volume is not currently attached to any VM
        if (volume.getInstanceId() != null) {
            throw new InvalidParameterValueException("Please specify a volume that is not attached to any VM.");
        }

        // Check that volume is completely Uploaded 
        if (volume.getState() == Volume.State.UploadOp){
            VolumeHostVO volumeHost = _volumeHostDao.findByVolumeId(volume.getId());
            if (volumeHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOAD_IN_PROGRESS){
                throw new InvalidParameterValueException("Please specify a volume that is not uploading");
            }            
        }

        // Check that the volume is not already destroyed
        if (volume.getState() != Volume.State.Destroy) {
            if (!destroyVolume(volume)) {
                return false;
            }
        }

        try {
            expungeVolume(volume, false);
        } catch (Exception e) {
            s_logger.warn("Failed to expunge volume:", e);
            return false;
        }

        return true;
    }

    private boolean validateVolumeSizeRange(long size) {
        if (size < 0 || (size > 0 && size < (1024 * 1024 * 1024))) {
            throw new InvalidParameterValueException("Please specify a size of at least 1 Gb.");
        } else if (size > (_maxVolumeSizeInGb * 1024 * 1024 * 1024)) {
            throw new InvalidParameterValueException("volume size " + size + ", but the maximum size allowed is " + _maxVolumeSizeInGb + " Gb.");
        }

        return true;
    }

    protected DiskProfile toDiskProfile(VolumeVO vol, DiskOfferingVO offering) {
        return new DiskProfile(vol.getId(), vol.getVolumeType(), vol.getName(), offering.getId(), vol.getSize(), offering.getTagsArray(), offering.getUseLocalStorage(), offering.isRecreatable(),
                vol.getTemplateId());
    }

    @Override
    public <T extends VMInstanceVO> DiskProfile allocateRawVolume(Type type, String name, DiskOfferingVO offering, Long size, T vm, Account owner) {
        if (size == null) {
            size = offering.getDiskSize();
        } else {
            size = (size * 1024 * 1024 * 1024);
        }
        VolumeVO vol = new VolumeVO(type, name, vm.getDataCenterId(), owner.getDomainId(), owner.getId(), offering.getId(), size);
        if (vm != null) {
            vol.setInstanceId(vm.getId());
        }

        if (type.equals(Type.ROOT)) {
            vol.setDeviceId(0l);
        } else {
            vol.setDeviceId(1l);
        }

        vol = _volsDao.persist(vol);

        // Save usage event and update resource count for user vm volumes
        if (vm instanceof UserVm) {
            UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_CREATE, vol.getAccountId(),
                    vol.getDataCenterId(), vol.getId(), vol.getName(), offering.getId(), null, size,
                    Volume.class.getName(), vol.getUuid());
            _resourceLimitMgr.incrementResourceCount(vm.getAccountId(), ResourceType.volume);
        }
        return toDiskProfile(vol, offering);
    }

    @Override
    public <T extends VMInstanceVO> DiskProfile allocateTemplatedVolume(Type type, String name, DiskOfferingVO offering, VMTemplateVO template, T vm, Account owner) {
        assert (template.getFormat() != ImageFormat.ISO) : "ISO is not a template really....";

        SearchCriteria<VMTemplateHostVO> sc = HostTemplateStatesSearch.create();
        sc.setParameters("id", template.getId());
        sc.setParameters("state", com.cloud.storage.VMTemplateStorageResourceAssoc.Status.DOWNLOADED);
        sc.setJoinParameters("host", "dcId", vm.getDataCenterId());
        List<VMTemplateSwiftVO> tsvs = _vmTemplateSwiftDao.listByTemplateId(template.getId());
        Long size = null;
        if (tsvs != null && tsvs.size() > 0) {
            size = tsvs.get(0).getSize();
        }

        if (size == null && _s3Mgr.isS3Enabled()) {
            VMTemplateS3VO vmTemplateS3VO = _vmTemplateS3Dao.findOneByTemplateId(template.getId());
            if (vmTemplateS3VO != null) {
                size = vmTemplateS3VO.getSize();
            }
        }

        if (size == null) {
            List<VMTemplateHostVO> sss = _vmTemplateHostDao.search(sc, null);
            if (sss == null || sss.size() == 0) {
                throw new CloudRuntimeException("Template " + template.getName() + " has not been completely downloaded to zone " + vm.getDataCenterId());
            }
            size = sss.get(0).getSize();
        }

        VolumeVO vol = new VolumeVO(type, name, vm.getDataCenterId(), owner.getDomainId(), owner.getId(), offering.getId(), size);
        if (vm != null) {
            vol.setInstanceId(vm.getId());
        }
        vol.setTemplateId(template.getId());

        if (type.equals(Type.ROOT)) {
            vol.setDeviceId(0l);
            if (!vm.getType().equals(VirtualMachine.Type.User)) {
                vol.setRecreatable(true);
            }
        } else {
            vol.setDeviceId(1l);
        }

        vol = _volsDao.persist(vol);

        // Create event and update resource count for volumes if vm is a user vm
        if (vm instanceof UserVm) {

            Long offeringId = null;

            if (offering.getType() == DiskOfferingVO.Type.Disk) {
                offeringId = offering.getId();
            }

            UsageEventUtils.publishUsageEvent(EventTypes.EVENT_VOLUME_CREATE, vol.getAccountId(),
                    vol.getDataCenterId(), vol.getId(), vol.getName(), offeringId, template.getId(),
                    vol.getSize(), Volume.class.getName(), vol.getUuid());

            _resourceLimitMgr.incrementResourceCount(vm.getAccountId(), ResourceType.volume);
        }
        return toDiskProfile(vol, offering);
    }

    @Override
    public void prepareForMigration(VirtualMachineProfile<? extends VirtualMachine> vm, DeployDestination dest) {
        List<VolumeVO> vols = _volsDao.findUsableVolumesForInstance(vm.getId());
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Preparing " + vols.size() + " volumes for " + vm);
        }

        for (VolumeVO vol : vols) {
            StoragePool pool = _storagePoolDao.findById(vol.getPoolId());
            vm.addDisk(new VolumeTO(vol, pool));
        }

        if (vm.getType() == VirtualMachine.Type.User) {
            UserVmVO userVM = (UserVmVO) vm.getVirtualMachine();
            if (userVM.getIsoId() != null) {
                Pair<String, String> isoPathPair = getAbsoluteIsoPath(userVM.getIsoId(), userVM.getDataCenterId());
                if (isoPathPair != null) {
                    String isoPath = isoPathPair.first();
                    VolumeTO iso = new VolumeTO(vm.getId(), Volume.Type.ISO, StoragePoolType.ISO, null, null, null, isoPath, 0, null, null);
                    vm.addDisk(iso);
                }
            }
        }
    }

    @DB
    @Override
    public Volume migrateVolume(Long volumeId, Long storagePoolId) throws ConcurrentOperationException {
        VolumeVO vol = _volsDao.findById(volumeId);
        if (vol == null) {
            throw new InvalidParameterValueException("Failed to find the volume id: " + volumeId);
        }

        if (vol.getState() != Volume.State.Ready) {
            throw new InvalidParameterValueException("Volume must be in ready state");
        }

        if (vol.getInstanceId() != null) {
            throw new InvalidParameterValueException("Volume needs to be dettached from VM");
        }

        StoragePool destPool = _storagePoolDao.findById(storagePoolId);
        if (destPool == null) {
            throw new InvalidParameterValueException("Failed to find the destination storage pool: " + storagePoolId);
        }

        if (!volumeOnSharedStoragePool(vol)) {
            throw new InvalidParameterValueException("Migration of volume from local storage pool is not supported");
        }

        List<Volume> vols = new ArrayList<Volume>();
        vols.add(vol);

        migrateVolumes(vols, destPool);
        return vol;
    }

    @DB
    public boolean migrateVolumes(List<Volume> volumes, StoragePool destPool) throws ConcurrentOperationException {
        Transaction txn = Transaction.currentTxn();
        txn.start();

        boolean transitResult = false;
        long checkPointTaskId = -1;
        try {
            List<Long> volIds = new ArrayList<Long>();
            for (Volume volume : volumes) {
                if (!_snapshotMgr.canOperateOnVolume((VolumeVO) volume)) {
                    throw new CloudRuntimeException("There are snapshots creating on this volume, can not move this volume");
                }

                try {
                    if (!stateTransitTo(volume, Volume.Event.MigrationRequested)) {
                        throw new ConcurrentOperationException("Failed to transit volume state");
                    }
                } catch (NoTransitionException e) {
                    s_logger.debug("Failed to set state into migrate: " + e.toString());
                    throw new CloudRuntimeException("Failed to set state into migrate: " + e.toString());
                }
                volIds.add(volume.getId());
            }

            transitResult = true;
        } finally {
            if (!transitResult) {
                txn.rollback();
            } else {
                txn.commit();
            }
        }

        // At this stage, nobody can modify volumes. Send the copyvolume command
        List<Pair<StoragePoolVO, DestroyCommand>> destroyCmds = new ArrayList<Pair<StoragePoolVO, DestroyCommand>>();
        List<CopyVolumeAnswer> answers = new ArrayList<CopyVolumeAnswer>();
        try {
            for (Volume volume : volumes) {
                String secondaryStorageURL = getSecondaryStorageURL(volume.getDataCenterId());
                StoragePoolVO srcPool = _storagePoolDao.findById(volume.getPoolId());
                CopyVolumeCommand cvCmd = new CopyVolumeCommand(volume.getId(), volume.getPath(), srcPool, secondaryStorageURL, true, _copyvolumewait);
                CopyVolumeAnswer cvAnswer;
                try {
                    cvAnswer = (CopyVolumeAnswer) sendToPool(srcPool, cvCmd);
                } catch (StorageUnavailableException e1) {
                    throw new CloudRuntimeException("Failed to copy the volume from the source primary storage pool to secondary storage.", e1);
                }

                if (cvAnswer == null || !cvAnswer.getResult()) {
                    throw new CloudRuntimeException("Failed to copy the volume from the source primary storage pool to secondary storage.");
                }

                String secondaryStorageVolumePath = cvAnswer.getVolumePath();

                // Copy the volume from secondary storage to the destination storage
                // pool
                cvCmd = new CopyVolumeCommand(volume.getId(), secondaryStorageVolumePath, destPool, secondaryStorageURL, false, _copyvolumewait);
                try {
                    cvAnswer = (CopyVolumeAnswer) sendToPool(destPool, cvCmd);
                } catch (StorageUnavailableException e1) {
                    throw new CloudRuntimeException("Failed to copy the volume from secondary storage to the destination primary storage pool.");
                }

                if (cvAnswer == null || !cvAnswer.getResult()) {
                    throw new CloudRuntimeException("Failed to copy the volume from secondary storage to the destination primary storage pool.");
                }

                answers.add(cvAnswer);
                destroyCmds.add(new Pair<StoragePoolVO, DestroyCommand>(srcPool, new DestroyCommand(srcPool, volume, null)));
            }
        } finally {
            if (answers.size() != volumes.size()) {
                // this means one of copying volume failed
                for (Volume volume : volumes) {
                    try {
                        stateTransitTo(volume, Volume.Event.OperationFailed);
                    } catch (NoTransitionException e) {
                        s_logger.debug("Failed to change volume state: " + e.toString());
                    }
                }
            } else {
                // Need a transaction, make sure all the volumes get migrated to new storage pool
                txn = Transaction.currentTxn();
                txn.start();

                transitResult = false;
                try {
                    for (int i = 0; i < volumes.size(); i++) {
                        CopyVolumeAnswer answer = answers.get(i);
                        VolumeVO volume = (VolumeVO) volumes.get(i);
                        Long oldPoolId = volume.getPoolId();
                        volume.setPath(answer.getVolumePath());
                        volume.setFolder(destPool.getPath());
                        volume.setPodId(destPool.getPodId());
                        volume.setPoolId(destPool.getId());
                        volume.setLastPoolId(oldPoolId);
                        volume.setPodId(destPool.getPodId());
                        try {
                            stateTransitTo(volume, Volume.Event.OperationSucceeded);
                        } catch (NoTransitionException e) {
                            s_logger.debug("Failed to change volume state: " + e.toString());
                            throw new CloudRuntimeException("Failed to change volume state: " + e.toString());
                        }
                    }
                    transitResult = true;
                } finally {
                    if (!transitResult) {
                        txn.rollback();
                    } else {
                        txn.commit();
                    }
                }

            }
        }

        // all the volumes get migrated to new storage pool, need to delete the copy on old storage pool
        for (Pair<StoragePoolVO, DestroyCommand> cmd : destroyCmds) {
            try {
                Answer cvAnswer = sendToPool(cmd.first(), cmd.second());
            } catch (StorageUnavailableException e) {
                s_logger.debug("Unable to delete the old copy on storage pool: " + e.toString());
            }
        }
        return true;
    }

    @Override
    public boolean StorageMigration(VirtualMachineProfile<? extends VirtualMachine> vm, StoragePool destPool) throws ConcurrentOperationException {
        List<VolumeVO> vols = _volsDao.findUsableVolumesForInstance(vm.getId());
        List<Volume> volumesNeedToMigrate = new ArrayList<Volume>();

        for (VolumeVO volume : vols) {
            if (volume.getState() != Volume.State.Ready) {
                s_logger.debug("volume: " + volume.getId() + " is in " + volume.getState() + " state");
                throw new CloudRuntimeException("volume: " + volume.getId() + " is in " + volume.getState() + " state");
            }

            if (volume.getPoolId() == destPool.getId()) {
                s_logger.debug("volume: " + volume.getId() + " is on the same storage pool: " + destPool.getId());
                continue;
            }

            volumesNeedToMigrate.add(volume);
        }

        if (volumesNeedToMigrate.isEmpty()) {
            s_logger.debug("No volume need to be migrated");
            return true;
        }

        return migrateVolumes(volumesNeedToMigrate, destPool);
    }

    @Override
    public void prepare(VirtualMachineProfile<? extends VirtualMachine> vm, DeployDestination dest) throws StorageUnavailableException, InsufficientStorageCapacityException {

        if (dest == null) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("DeployDestination cannot be null, cannot prepare Volumes for the vm: " + vm);
            }
            throw new CloudRuntimeException("Unable to prepare Volume for vm because DeployDestination is null, vm:" + vm);
        }
        List<VolumeVO> vols = _volsDao.findUsableVolumesForInstance(vm.getId());
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Checking if we need to prepare " + vols.size() + " volumes for " + vm);
        }

        boolean recreate = _recreateSystemVmEnabled;

        List<VolumeVO> recreateVols = new ArrayList<VolumeVO>(vols.size());

        for (VolumeVO vol : vols) {
            StoragePool assignedPool = null;
            if (dest.getStorageForDisks() != null) {
                assignedPool = dest.getStorageForDisks().get(vol);
            }
            if (assignedPool == null && recreate) {
                assignedPool = _storagePoolDao.findById(vol.getPoolId());

            }
            if (assignedPool != null || recreate) {
                Volume.State state = vol.getState();
                if (state == Volume.State.Allocated || state == Volume.State.Creating) {
                    recreateVols.add(vol);
                } else {
                    if (vol.isRecreatable()) {
                        if (s_logger.isDebugEnabled()) {
                            s_logger.debug("Volume " + vol + " will be recreated on storage pool " + assignedPool + " assigned by deploymentPlanner");
                        }
                        recreateVols.add(vol);
                    } else {
                        if (assignedPool.getId() != vol.getPoolId()) {
                            if (s_logger.isDebugEnabled()) {
                                s_logger.debug("Mismatch in storage pool " + assignedPool + " assigned by deploymentPlanner and the one associated with volume " + vol);
                            }
                            DiskOfferingVO diskOffering = _diskOfferingDao.findById(vol.getDiskOfferingId());
                            if (diskOffering.getUseLocalStorage())
                            {
                                if (s_logger.isDebugEnabled()) {
                                    s_logger.debug("Local volume " + vol + " will be recreated on storage pool " + assignedPool + " assigned by deploymentPlanner");
                                }
                                recreateVols.add(vol);
                            } else {
                                if (s_logger.isDebugEnabled()) {
                                    s_logger.debug("Shared volume " + vol + " will be migrated on storage pool " + assignedPool + " assigned by deploymentPlanner");
                                }
                                try {
                                    List<Volume> volumesToMigrate = new ArrayList<Volume>();
                                    volumesToMigrate.add(vol);
                                    migrateVolumes(volumesToMigrate, assignedPool);
                                    vm.addDisk(new VolumeTO(vol, assignedPool));
                                } catch (ConcurrentOperationException e) {
                                    throw new CloudRuntimeException("Migration of volume " + vol + " to storage pool " + assignedPool + " failed", e);
                                }
                            }
                        } else {
                            StoragePoolVO pool = _storagePoolDao.findById(vol.getPoolId());
                            vm.addDisk(new VolumeTO(vol, pool));
                        }

                    }
                }
            } else {
                if (vol.getPoolId() == null) {
                    throw new StorageUnavailableException("Volume has no pool associate and also no storage pool assigned in DeployDestination, Unable to create " + vol, Volume.class, vol.getId());
                }
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("No need to recreate the volume: " + vol + ", since it already has a pool assigned: " + vol.getPoolId() + ", adding disk to VM");
                }
                StoragePoolVO pool = _storagePoolDao.findById(vol.getPoolId());
                vm.addDisk(new VolumeTO(vol, pool));
            }
        }

        for (VolumeVO vol : recreateVols) {
            VolumeVO newVol;
            StoragePool existingPool = null;
            if (recreate && (dest.getStorageForDisks() == null || dest.getStorageForDisks().get(vol) == null)) {
                existingPool = _storagePoolDao.findById(vol.getPoolId());
                s_logger.debug("existing pool: " + existingPool.getId());
            }

            if (vol.getState() == Volume.State.Allocated || vol.getState() == Volume.State.Creating) {
                newVol = vol;
            } else {
                newVol = switchVolume(vol, vm);
                // update the volume->storagePool map since volumeId has changed
                if (dest.getStorageForDisks() != null && dest.getStorageForDisks().containsKey(vol)) {
                    StoragePool poolWithOldVol = dest.getStorageForDisks().get(vol);
                    dest.getStorageForDisks().put(newVol, poolWithOldVol);
                    dest.getStorageForDisks().remove(vol);
                }
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("Created new volume " + newVol + " for old volume " + vol);
                }
            }

            try {
                stateTransitTo(newVol, Volume.Event.CreateRequested);
            } catch (NoTransitionException e) {
                throw new CloudRuntimeException("Unable to create " + e.toString());
            }

            Pair<VolumeTO, StoragePool> created = createVolume(newVol, _diskOfferingDao.findById(newVol.getDiskOfferingId()), vm, vols, dest, existingPool);

            if (created == null) {
                Long poolId = newVol.getPoolId();
                newVol.setPoolId(null);
                try {
                    stateTransitTo(newVol, Volume.Event.OperationFailed);
                } catch (NoTransitionException e) {
                    throw new CloudRuntimeException("Unable to update the failure on a volume: " + newVol, e);
                }
                throw new StorageUnavailableException("Unable to create " + newVol, poolId == null ? -1L : poolId);
            }
            created.first().setDeviceId(newVol.getDeviceId().intValue());
            newVol.setFolder(created.second().getPath());
            newVol.setPath(created.first().getPath());
            newVol.setSize(created.first().getSize());
            newVol.setPoolType(created.second().getPoolType());
            newVol.setPodId(created.second().getPodId());
            try {
                stateTransitTo(newVol, Volume.Event.OperationSucceeded);
            } catch (NoTransitionException e) {
                throw new CloudRuntimeException("Unable to update an CREATE operation succeeded on volume " + newVol, e);
            }
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Volume " + newVol + " is created on " + created.second());
            }

            vm.addDisk(created.first());
        }
    }

    @DB
    protected VolumeVO switchVolume(VolumeVO existingVolume, VirtualMachineProfile<? extends VirtualMachine> vm) throws StorageUnavailableException {
        Transaction txn = Transaction.currentTxn();

        Long templateIdToUse = null;
        Long volTemplateId = existingVolume.getTemplateId();
        long vmTemplateId = vm.getTemplateId();
        if (volTemplateId != null && volTemplateId.longValue() != vmTemplateId) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("switchVolume: Old Volume's templateId: " + volTemplateId + " does not match the VM's templateId: " + vmTemplateId + ", updating templateId in the new Volume");
            }
            templateIdToUse = vmTemplateId;
        }

        txn.start();
        VolumeVO newVolume = allocateDuplicateVolume(existingVolume, templateIdToUse);
        // In case of Vmware if vm reference is not removed then during root disk cleanup
        // the vm also gets deleted, so remove the reference
        if (vm.getHypervisorType() == HypervisorType.VMware) {
            _volsDao.detachVolume(existingVolume.getId());
        }
        try {
            stateTransitTo(existingVolume, Volume.Event.DestroyRequested);
        } catch (NoTransitionException e) {
            s_logger.debug("Unable to destroy existing volume: " + e.toString());
        }
        txn.commit();
        return newVolume;

    }

    public Pair<VolumeTO, StoragePool> createVolume(VolumeVO toBeCreated, DiskOfferingVO offering, VirtualMachineProfile<? extends VirtualMachine> vm, List<? extends Volume> alreadyCreated,
            DeployDestination dest, StoragePool sPool) throws StorageUnavailableException {
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Creating volume: " + toBeCreated);
        }
        DiskProfile diskProfile = new DiskProfile(toBeCreated, offering, vm.getHypervisorType());

        VMTemplateVO template = null;
        if (toBeCreated.getTemplateId() != null) {
            template = _templateDao.findById(toBeCreated.getTemplateId());
        }

        StoragePool pool = null;
        if (sPool != null) {
            pool = sPool;
        } else {
            pool = dest.getStorageForDisks().get(toBeCreated);
        }

        if (pool != null) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Trying to create in " + pool);
            }
            toBeCreated.setPoolId(pool.getId());
            try {
                stateTransitTo(toBeCreated, Volume.Event.OperationRetry);
            } catch (NoTransitionException e) {
                throw new CloudRuntimeException("Unable to retry a create operation on volume " + toBeCreated);
            }

            CreateCommand cmd = null;
            VMTemplateStoragePoolVO tmpltStoredOn = null;

            for (int i = 0; i < 2; i++) {
                if (template != null && template.getFormat() != Storage.ImageFormat.ISO) {
                    if (pool.getPoolType() == StoragePoolType.CLVM) {
                        //prepareISOForCreate does what we need, which is to tell us where the template is
                        VMTemplateHostVO tmpltHostOn = _tmpltMgr.prepareISOForCreate(template, pool);
                        if (tmpltHostOn == null) {
                            s_logger.debug("cannot find template " + template.getId() + " " + template.getName());
                            return null;
                        }
                        HostVO secondaryStorageHost = _hostDao.findById(tmpltHostOn.getHostId());
                        String tmpltHostUrl = secondaryStorageHost.getStorageUrl();
                        String fullTmpltUrl = tmpltHostUrl + "/" + tmpltHostOn.getInstallPath();
                        cmd = new CreateCommand(diskProfile, fullTmpltUrl, new StorageFilerTO(pool));
                    } else {
                        tmpltStoredOn = _tmpltMgr.prepareTemplateForCreate(template, pool);
                        if (tmpltStoredOn == null) {
                            s_logger.debug("Cannot use this pool " + pool + " because we can't propagate template " + template);
                            return null;
                        }
                        cmd = new CreateCommand(diskProfile, tmpltStoredOn.getLocalDownloadPath(), new StorageFilerTO(pool));
                    }
                } else {
                    if (template != null && Storage.ImageFormat.ISO == template.getFormat()) {
                        VMTemplateHostVO tmpltHostOn = _tmpltMgr.prepareISOForCreate(template, pool);
                        if (tmpltHostOn == null) {
                            throw new CloudRuntimeException("Did not find ISO in secondry storage in zone " + pool.getDataCenterId());
                        }
                    }
                    cmd = new CreateCommand(diskProfile, new StorageFilerTO(pool));
                }
                long[] hostIdsToTryFirst = { dest.getHost().getId() };
                Answer answer = sendToPool(pool, hostIdsToTryFirst, cmd);
                if (answer.getResult()) {
                    CreateAnswer createAnswer = (CreateAnswer) answer;
                    return new Pair<VolumeTO, StoragePool>(createAnswer.getVolume(), pool);
                } else {
                    if (tmpltStoredOn != null && (answer instanceof CreateAnswer) && ((CreateAnswer) answer).templateReloadRequested()) {
                        if (!_tmpltMgr.resetTemplateDownloadStateOnPool(tmpltStoredOn.getId())) {
                            break; // break out of template-redeploy retry loop
                        }
                    } else {
                        break;
                    }
                }
            }
        }

        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Unable to create volume " + toBeCreated);
        }
        return null;
    }

    @Override
    public void release(VirtualMachineProfile<? extends VMInstanceVO> profile) {
        // add code here
    }

    public void expungeVolume(VolumeVO vol, boolean force) {
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Expunging " + vol);
        }

        //Find out if the volume is present on secondary storage
        VolumeHostVO volumeHost = _volumeHostDao.findByVolumeId(vol.getId());
        if(volumeHost != null){
            if (volumeHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOADED){
                HostVO ssHost = _hostDao.findById(volumeHost.getHostId());
                DeleteVolumeCommand dtCommand = new DeleteVolumeCommand(ssHost.getStorageUrl(), volumeHost.getInstallPath());            
                Answer answer = _agentMgr.sendToSecStorage(ssHost, dtCommand);
                if (answer == null || !answer.getResult()) {
                    s_logger.debug("Failed to delete " + volumeHost + " due to " + ((answer == null) ? "answer is null" : answer.getDetails()));
                    return;
                }
            }else if(volumeHost.getDownloadState() == VMTemplateStorageResourceAssoc.Status.DOWNLOAD_IN_PROGRESS){									
                s_logger.debug("Volume: " + vol.getName() + " is currently being uploaded; cant' delete it.");
                throw new CloudRuntimeException("Please specify a volume that is not currently being uploaded.");
            }
            _volumeHostDao.remove(volumeHost.getId());
            _volumeDao.remove(vol.getId());
            return;             
        }

        String vmName = null;
        if (vol.getVolumeType() == Type.ROOT && vol.getInstanceId() != null) {
            VirtualMachine vm = _vmInstanceDao.findByIdIncludingRemoved(vol.getInstanceId());
            if (vm != null) {
                vmName = vm.getInstanceName();
            }
        }

        String volumePath = vol.getPath();
        Long poolId = vol.getPoolId();
        if (poolId == null || volumePath == null || volumePath.trim().isEmpty()) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Marking volume that was never created as destroyed: " + vol);
            }
            _volsDao.remove(vol.getId());
            return;
        }

        StoragePoolVO pool = _storagePoolDao.findById(poolId);
        if (pool == null) {
            s_logger.debug("Removing volume as storage pool is gone: " + poolId);
            _volsDao.remove(vol.getId());
            return;
        }

        DestroyCommand cmd = new DestroyCommand(pool, vol, vmName);
        boolean removeVolume = false;
        try {
            Answer answer = sendToPool(pool, cmd);
            if (answer != null && answer.getResult()) {
                removeVolume = true;
            } else {
                s_logger.info("Will retry delete of " + vol + " from " + poolId);
            }
        } catch (StorageUnavailableException e) {
            if (force) {
                s_logger.info("Storage is unavailable currently, but marking volume id=" + vol.getId() + " as expunged anyway due to force=true");
                removeVolume = true;
            } else {
                s_logger.info("Storage is unavailable currently.  Will retry delete of " + vol + " from " + poolId);
            }
        } catch (RuntimeException ex) {
            if (force) {
                s_logger.info("Failed to expunge volume, but marking volume id=" + vol.getId() + " as expunged anyway " +
                        "due to force=true. Volume failed to expunge due to ", ex);
                removeVolume = true;
            } else {
                throw ex;
            }
        } finally {
            if (removeVolume) {
                _volsDao.remove(vol.getId());
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("Volume successfully expunged from " + poolId);
                }
            }
        }

    }

    @Override
    @DB
    public void cleanupVolumes(long vmId) throws ConcurrentOperationException {
        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Cleaning storage for vm: " + vmId);
        }
        List<VolumeVO> volumesForVm = _volsDao.findByInstance(vmId);
        List<VolumeVO> toBeExpunged = new ArrayList<VolumeVO>();
        Transaction txn = Transaction.currentTxn();
        txn.start();
        for (VolumeVO vol : volumesForVm) {
            if (vol.getVolumeType().equals(Type.ROOT)) {
                // This check is for VM in Error state (volume is already destroyed)
                if (!vol.getState().equals(Volume.State.Destroy)) {
                    destroyVolume(vol);
                }
                toBeExpunged.add(vol);
            } else {
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("Detaching " + vol);
                }
                _volsDao.detachVolume(vol.getId());
            }
        }
        txn.commit();

        for (VolumeVO expunge : toBeExpunged) {
            expungeVolume(expunge, false);
        }
    }

    protected class StorageGarbageCollector implements Runnable {

        public StorageGarbageCollector() {
        }

        @Override
        public void run() {
            try {
                s_logger.trace("Storage Garbage Collection Thread is running.");

                cleanupStorage(true);

            } catch (Exception e) {
                s_logger.error("Caught the following Exception", e);
            }
        }
    }

    @Override
    public void onManagementNodeJoined(List<ManagementServerHostVO> nodeList, long selfNodeId) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onManagementNodeLeft(List<ManagementServerHostVO> nodeList, long selfNodeId) {
        for (ManagementServerHostVO vo : nodeList) {
            if (vo.getMsid() == _serverId) {
                s_logger.info("Cleaning up storage maintenance jobs associated with Management server" + vo.getMsid());
                List<Long> poolIds = _storagePoolWorkDao.searchForPoolIdsForPendingWorkJobs(vo.getMsid());
                if (poolIds.size() > 0) {
                    for (Long poolId : poolIds) {
                        StoragePoolVO pool = _storagePoolDao.findById(poolId);
                        // check if pool is in an inconsistent state
                        if (pool != null
                                && (pool.getStatus().equals(StoragePoolStatus.ErrorInMaintenance) || pool.getStatus().equals(StoragePoolStatus.PrepareForMaintenance) || pool.getStatus().equals(
                                        StoragePoolStatus.CancelMaintenance))) {
                            _storagePoolWorkDao.removePendingJobsOnMsRestart(vo.getMsid(), poolId);
                            pool.setStatus(StoragePoolStatus.ErrorInMaintenance);
                            _storagePoolDao.update(poolId, pool);
                        }

                    }
                }
            }
        }
    }

    @Override
    public void onManagementNodeIsolated() {
    }

    @Override
    public CapacityVO getSecondaryStorageUsedStats(Long hostId, Long zoneId) {
        SearchCriteria<HostVO> sc = _hostDao.createSearchCriteria();
        if (zoneId != null) {
            sc.addAnd("dataCenterId", SearchCriteria.Op.EQ, zoneId);
        }

        List<HostVO> hosts = new ArrayList<HostVO>();
        if (hostId != null) {
            hosts.add(ApiDBUtils.findHostById(hostId));
        } else {
            hosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(zoneId);
        }

        CapacityVO capacity = new CapacityVO(hostId, zoneId, null, null, 0, 0, CapacityVO.CAPACITY_TYPE_SECONDARY_STORAGE);
        for (HostVO host : hosts) {
            StorageStats stats = ApiDBUtils.getSecondaryStorageStatistics(host.getId());
            if (stats == null) {
                continue;
            }
            capacity.setUsedCapacity(stats.getByteUsed() + capacity.getUsedCapacity());
            capacity.setTotalCapacity(stats.getCapacityBytes() + capacity.getTotalCapacity());
        }

        return capacity;
    }

    @Override
    public CapacityVO getStoragePoolUsedStats(Long poolId, Long clusterId, Long podId, Long zoneId) {
        SearchCriteria<StoragePoolVO> sc = _storagePoolDao.createSearchCriteria();
        List<StoragePoolVO> pools = new ArrayList<StoragePoolVO>();

        if (zoneId != null) {
            sc.addAnd("dataCenterId", SearchCriteria.Op.EQ, zoneId);
        }

        if (podId != null) {
            sc.addAnd("podId", SearchCriteria.Op.EQ, podId);
        }

        if (clusterId != null) {
            sc.addAnd("clusterId", SearchCriteria.Op.EQ, clusterId);
        }

        if (poolId != null) {
            sc.addAnd("hostOrPoolId", SearchCriteria.Op.EQ, poolId);
        }
        if (poolId != null) {
            pools.add(_storagePoolDao.findById(poolId));
        } else {
            pools = _storagePoolDao.search(sc, null);
        }

        CapacityVO capacity = new CapacityVO(poolId, zoneId, podId, clusterId, 0, 0, CapacityVO.CAPACITY_TYPE_STORAGE);
        for (StoragePoolVO storagePool : pools) {
            StorageStats stats = ApiDBUtils.getStoragePoolStatistics(storagePool.getId());
            if (stats == null) {
                continue;
            }
            capacity.setUsedCapacity(stats.getByteUsed() + capacity.getUsedCapacity());
            capacity.setTotalCapacity(stats.getCapacityBytes() + capacity.getTotalCapacity());
        }
        return capacity;
    }

    @Override
    public StoragePool getStoragePool(long id) {
        return _storagePoolDao.findById(id);
    }

    @Override
    public VMTemplateHostVO findVmTemplateHost(long templateId, StoragePool pool) {
        long dcId = pool.getDataCenterId();
        Long podId = pool.getPodId();

        List<HostVO> secHosts = _ssvmMgr.listSecondaryStorageHostsInOneZone(dcId);

        // FIXME, for cloudzone, the local secondary storoge
        if (pool.isLocal() && pool.getPoolType() == StoragePoolType.Filesystem && secHosts.isEmpty()) {
            List<StoragePoolHostVO> sphs = _storagePoolHostDao.listByPoolId(pool.getId());
            if (!sphs.isEmpty()) {
                StoragePoolHostVO localStoragePoolHost = sphs.get(0);
                return _templateHostDao.findLocalSecondaryStorageByHostTemplate(localStoragePoolHost.getHostId(), templateId);
            } else {
                return null;
            }
        }

        if (secHosts.size() == 1) {
            VMTemplateHostVO templateHostVO = _templateHostDao.findByHostTemplate(secHosts.get(0).getId(), templateId);
            return templateHostVO;
        }
        if (podId != null) {
            List<VMTemplateHostVO> templHosts = _templateHostDao.listByTemplateStatus(templateId, dcId, podId, VMTemplateStorageResourceAssoc.Status.DOWNLOADED);
            if (templHosts != null && !templHosts.isEmpty()) {
                Collections.shuffle(templHosts);
                return templHosts.get(0);
            }
        }
        List<VMTemplateHostVO> templHosts = _templateHostDao.listByTemplateStatus(templateId, dcId, VMTemplateStorageResourceAssoc.Status.DOWNLOADED);
        if (templHosts != null && !templHosts.isEmpty()) {
            Collections.shuffle(templHosts);
            return templHosts.get(0);
        }
        return null;
    }

    @Override
    @DB
    public List<VMInstanceVO> listByStoragePool(long storagePoolId) {
        SearchCriteria<VMInstanceVO> sc = StoragePoolSearch.create();
        sc.setJoinParameters("vmVolume", "volumeType", Volume.Type.ROOT);
        sc.setJoinParameters("vmVolume", "poolId", storagePoolId);
        return _vmInstanceDao.search(sc, null);
    }

    @Override
    @DB
    public StoragePoolVO findLocalStorageOnHost(long hostId) {
        SearchCriteria<StoragePoolVO> sc = LocalStorageSearch.create();
        sc.setParameters("type", new Object[] { StoragePoolType.Filesystem, StoragePoolType.LVM });
        sc.setJoinParameters("poolHost", "hostId", hostId);
        List<StoragePoolVO> storagePools = _storagePoolDao.search(sc, null);
        if (!storagePools.isEmpty()) {
            return storagePools.get(0);
        } else {
            return null;
        }
    }

    @Override
    public Host updateSecondaryStorage(long secStorageId, String newUrl) {
        HostVO secHost = _hostDao.findById(secStorageId);
        if (secHost == null) {
            throw new InvalidParameterValueException("Can not find out the secondary storage id: " + secStorageId);
        }

        if (secHost.getType() != Host.Type.SecondaryStorage) {
            throw new InvalidParameterValueException("host: " + secStorageId + " is not a secondary storage");
        }

        URI uri = null;
        try {
            uri = new URI(UriUtils.encodeURIComponent(newUrl));
            if (uri.getScheme() == null) {
                throw new InvalidParameterValueException("uri.scheme is null " + newUrl + ", add nfs:// as a prefix");
            } else if (uri.getScheme().equalsIgnoreCase("nfs")) {
                if (uri.getHost() == null || uri.getHost().equalsIgnoreCase("") || uri.getPath() == null || uri.getPath().equalsIgnoreCase("")) {
                    throw new InvalidParameterValueException("Your host and/or path is wrong.  Make sure it's of the format nfs://hostname/path");
                }
            }
        } catch (URISyntaxException e) {
            throw new InvalidParameterValueException(newUrl + " is not a valid uri");
        }

        String oldUrl = secHost.getStorageUrl();

        URI oldUri = null;
        try {
            oldUri = new URI(UriUtils.encodeURIComponent(oldUrl));
            if (!oldUri.getScheme().equalsIgnoreCase(uri.getScheme())) {
                throw new InvalidParameterValueException("can not change old scheme:" + oldUri.getScheme() + " to " + uri.getScheme());
            }
        } catch (URISyntaxException e) {
            s_logger.debug("Failed to get uri from " + oldUrl);
        }

        secHost.setStorageUrl(newUrl);
        secHost.setGuid(newUrl);
        secHost.setName(newUrl);
        _hostDao.update(secHost.getId(), secHost);
        return secHost;
    }


    @Override
    public String getSupportedImageFormatForCluster(Long clusterId) {
        ClusterVO cluster = ApiDBUtils.findClusterById(clusterId);

        if (cluster.getHypervisorType() == HypervisorType.XenServer) {
            return "vhd";
        } else if (cluster.getHypervisorType() == HypervisorType.KVM) {
            return "qcow2";
        } else if (cluster.getHypervisorType() == HypervisorType.VMware) {
            return "ova";
        } else if (cluster.getHypervisorType() == HypervisorType.Ovm) {
            return "raw";
        } else {
            return null;
        }
    }

    @Override
    public HypervisorType getHypervisorTypeFromFormat(ImageFormat format) {

        if(format == null) {
            return HypervisorType.None;
        }

        if (format == ImageFormat.VHD) {
            return HypervisorType.XenServer;
        } else if (format == ImageFormat.OVA) {
            return HypervisorType.VMware;
        } else if (format == ImageFormat.QCOW2) {
            return HypervisorType.KVM;
        } else if (format == ImageFormat.RAW) {
            return HypervisorType.Ovm;
        } else {
            return HypervisorType.None;
        }
    }

    private boolean checkUsagedSpace(StoragePool pool){
        StatsCollector sc = StatsCollector.getInstance();
        if (sc != null) {
            long totalSize = pool.getCapacityBytes();
            StorageStats stats = sc.getStoragePoolStats(pool.getId());
            if(stats == null){
                stats = sc.getStorageStats(pool.getId());
            }
            if (stats != null) {
                double usedPercentage = ((double)stats.getByteUsed() / (double)totalSize);
                if (s_logger.isDebugEnabled()) {
                    s_logger.debug("Checking pool " + pool.getId() + " for storage, totalSize: " + pool.getCapacityBytes() + ", usedBytes: " + stats.getByteUsed() + ", usedPct: " + usedPercentage + ", disable threshold: " + _storageUsedThreshold);
                }
                if (usedPercentage >= _storageUsedThreshold) {
                    if (s_logger.isDebugEnabled()) {
                        s_logger.debug("Insufficient space on pool: " + pool.getId() + " since its usage percentage: " +usedPercentage + " has crossed the pool.storage.capacity.disablethreshold: " + _storageUsedThreshold);
                    }
                    return false;
                }
            }
            return true;
        }
        return false;
    }

    @Override
    public boolean storagePoolHasEnoughSpace(List<Volume> volumes, StoragePool pool) {
        if(volumes == null || volumes.isEmpty())
            return false;

        if(!checkUsagedSpace(pool))
            return false;

        // allocated space includes template of specified volume
        StoragePoolVO poolVO = _storagePoolDao.findById(pool.getId());
        long allocatedSizeWithtemplate = _capacityMgr.getAllocatedPoolCapacity(poolVO, null);
        long totalAskingSize = 0;
        for (Volume volume : volumes) {
            if(volume.getTemplateId()!=null){
                VMTemplateVO tmpl = _templateDao.findById(volume.getTemplateId());
                if (tmpl.getFormat() != ImageFormat.ISO){
                    allocatedSizeWithtemplate = _capacityMgr.getAllocatedPoolCapacity(poolVO, tmpl);
                }
            }
            if(volume.getState() != Volume.State.Ready)
                totalAskingSize = totalAskingSize + volume.getSize();
        }

        long totalOverProvCapacity;
        if (pool.getPoolType() == StoragePoolType.NetworkFilesystem) {
            totalOverProvCapacity = _storageOverprovisioningFactor.multiply(new BigDecimal(pool.getCapacityBytes())).longValue();// All this for the inaccuracy of floats for big number multiplication.
        }else {
            totalOverProvCapacity = pool.getCapacityBytes();
        }

        if (s_logger.isDebugEnabled()) {
            s_logger.debug("Checking pool: " + pool.getId() + " for volume allocation " + volumes.toString() + ", maxSize : " + totalOverProvCapacity + ", totalAllocatedSize : " + allocatedSizeWithtemplate + ", askingSize : " + totalAskingSize + ", allocated disable threshold: " + _storageAllocatedThreshold);
        }

        double usedPercentage = (allocatedSizeWithtemplate + totalAskingSize) / (double)(totalOverProvCapacity);
        if (usedPercentage > _storageAllocatedThreshold){
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Insufficient un-allocated capacity on: " + pool.getId() + " for volume allocation: " + volumes.toString() + " since its allocated percentage: " +usedPercentage + " has crossed the allocated pool.storage.allocated.capacity.disablethreshold: " + _storageAllocatedThreshold + ", skipping this pool");
            }
            return false;
        }

        if (totalOverProvCapacity < (allocatedSizeWithtemplate + totalAskingSize)) {
            if (s_logger.isDebugEnabled()) {
                s_logger.debug("Insufficient un-allocated capacity on: " + pool.getId() + " for volume allocation: " + volumes.toString() + ", not enough storage, maxSize : " + totalOverProvCapacity + ", totalAllocatedSize : " + allocatedSizeWithtemplate + ", askingSize : " + totalAskingSize);
            }
            return false;
        }
        return true;
    }

}