conf/jvm.options - cassandra - Git at Google

 ###########################################################################
 #                             jvm.options                                 #
 #                                                                         #
 # - all flags defined here will be used by cassandra to startup the JVM   #
 # - one flag should be specified per line                                 #
 # - lines that do not start with '-' will be ignored                      #
 # - only static flags are accepted (no variables or parameters)           #
 # - dynamic flags will be appended to these on cassandra-env              #
 ###########################################################################

 ######################
 # STARTUP PARAMETERS #
 ######################

 # Uncomment any of the following properties to enable specific startup parameters

 # In a multi-instance deployment, multiple Cassandra instances will independently assume that all
 # CPU processors are available to it. This setting allows you to specify a smaller set of processors
 # and perhaps have affinity.
 #-Dcassandra.available_processors=number_of_processors

 # The directory location of the cassandra.yaml file.
 #-Dcassandra.config=directory

 # Sets the initial partitioner token for a node the first time the node is started.
 #-Dcassandra.initial_token=token

 # Set to false to start Cassandra on a node but not have the node join the cluster.
 #-Dcassandra.join_ring=true|false

 # Set to false to clear all gossip state for the node on restart. Use when you have changed node
 # information in cassandra.yaml (such as listen_address).
 #-Dcassandra.load_ring_state=true|false

 # Enable pluggable metrics reporter. See Pluggable metrics reporting in Cassandra 2.0.2.
 #-Dcassandra.metricsReporterConfigFile=file

 # Set the port on which the CQL native transport listens for clients. (Default: 9042)
 #-Dcassandra.native_transport_port=port

 # Overrides the partitioner. (Default: org.apache.cassandra.dht.Murmur3Partitioner)
 #-Dcassandra.partitioner=partitioner

 # To replace a node that has died, restart a new node in its place specifying the address of the
 # dead node. The new node must not have any data in its data directory, that is, it must be in the
 # same state as before bootstrapping.
 #-Dcassandra.replace_address=listen_address or broadcast_address of dead node

 # Allow restoring specific tables from an archived commit log.
 #-Dcassandra.replayList=table

 # Allows overriding of the default RING_DELAY (1000ms), which is the amount of time a node waits
 # before joining the ring.
 #-Dcassandra.ring_delay_ms=ms

 # Set the port for the Thrift RPC service, which is used for client connections. (Default: 9160)
 #-Dcassandra.rpc_port=port

 # Set the SSL port for encrypted communication. (Default: 7001)
 #-Dcassandra.ssl_storage_port=port

 # Enable or disable the native transport server. See start_native_transport in cassandra.yaml.
 # cassandra.start_native_transport=true|false

 # Enable or disable the Thrift RPC server. (Default: true)
 #-Dcassandra.start_rpc=true/false

 # Set the port for inter-node communication. (Default: 7000)
 #-Dcassandra.storage_port=port

 # Set the default location for the trigger JARs. (Default: conf/triggers)
 #-Dcassandra.triggers_dir=directory

 # For testing new compaction and compression strategies. It allows you to experiment with different
 # strategies and benchmark write performance differences without affecting the production workload.
 #-Dcassandra.write_survey=true

 # To disable configuration via JMX of auth caches (such as those for credentials, permissions and
 # roles). This will mean those config options can only be set (persistently) in cassandra.yaml
 # and will require a restart for new values to take effect.
 #-Dcassandra.disable_auth_caches_remote_configuration=true

 ########################
 # GENERAL JVM SETTINGS #
 ########################

 # enable assertions.  disabling this in production will give a modest
 # performance benefit (around 5%).
 -ea

 # enable thread priorities, primarily so we can give periodic tasks
 # a lower priority to avoid interfering with client workload
 -XX:+UseThreadPriorities

 # allows lowering thread priority without being root on linux - probably
 # not necessary on Windows but doesn't harm anything.
 # see http://tech.stolsvik.com/2010/01/linux-java-thread-priorities-workar
 -XX:ThreadPriorityPolicy=42

 # Enable heap-dump if there's an OOM
 -XX:+HeapDumpOnOutOfMemoryError

 # Per-thread stack size.
 -Xss256k

 # Larger interned string table, for gossip's benefit (CASSANDRA-6410)
 -XX:StringTableSize=1000003

 # Make sure all memory is faulted and zeroed on startup.
 # This helps prevent soft faults in containers and makes
 # transparent hugepage allocation more effective.
 -XX:+AlwaysPreTouch

 # Disable biased locking as it does not benefit Cassandra.
 -XX:-UseBiasedLocking

 # Enable thread-local allocation blocks and allow the JVM to automatically
 # resize them at runtime.
 -XX:+UseTLAB
 -XX:+ResizeTLAB

 # http://www.evanjones.ca/jvm-mmap-pause.html
 -XX:+PerfDisableSharedMem

 # Prefer binding to IPv4 network intefaces (when net.ipv6.bindv6only=1). See
 # http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6342561 (short version:
 # comment out this entry to enable IPv6 support).
 -Djava.net.preferIPv4Stack=true

 ### Debug options

 # uncomment to enable flight recorder
 #-XX:+UnlockCommercialFeatures
 #-XX:+FlightRecorder

 # uncomment to have Cassandra JVM listen for remote debuggers/profilers on port 1414
 #-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1414

 # uncomment to have Cassandra JVM log internal method compilation (developers only)
 #-XX:+UnlockDiagnosticVMOptions
 #-XX:+LogCompilation

 #################
 # HEAP SETTINGS #
 #################

 # Heap size is automatically calculated by cassandra-env based on this
 # formula: max(min(1/2 ram, 1024MB), min(1/4 ram, 8GB))
 # That is:
 # - calculate 1/2 ram and cap to 1024MB
 # - calculate 1/4 ram and cap to 8192MB
 # - pick the max
 #
 # For production use you may wish to adjust this for your environment.
 # If that's the case, uncomment the -Xmx and Xms options below to override the
 # automatic calculation of JVM heap memory.
 #
 # It is recommended to set min (-Xms) and max (-Xmx) heap sizes to
 # the same value to avoid stop-the-world GC pauses during resize, and
 # so that we can lock the heap in memory on startup to prevent any
 # of it from being swapped out.
 #-Xms4G
 #-Xmx4G

 # Young generation size is automatically calculated by cassandra-env
 # based on this formula: min(100 * num_cores, 1/4 * heap size)
 #
 # The main trade-off for the young generation is that the larger it
 # is, the longer GC pause times will be. The shorter it is, the more
 # expensive GC will be (usually).
 #
 # It is not recommended to set the young generation size if using the
 # G1 GC, since that will override the target pause-time goal.
 # More info: http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html
 #
 # The example below assumes a modern 8-core+ machine for decent
 # times. If in doubt, and if you do not particularly want to tweak, go
 # 100 MB per physical CPU core.
 #-Xmn800M

 #################
 #  GC SETTINGS  #
 #################

 ### CMS Settings

 -XX:+UseParNewGC
 -XX:+UseConcMarkSweepGC
 -XX:+CMSParallelRemarkEnabled
 -XX:SurvivorRatio=8
 -XX:MaxTenuringThreshold=1
 -XX:CMSInitiatingOccupancyFraction=75
 -XX:+UseCMSInitiatingOccupancyOnly
 -XX:CMSWaitDuration=10000
 -XX:+CMSParallelInitialMarkEnabled
 -XX:+CMSEdenChunksRecordAlways
 # some JVMs will fill up their heap when accessed via JMX, see CASSANDRA-6541
 -XX:+CMSClassUnloadingEnabled

 ### G1 Settings (experimental, comment previous section and uncomment section below to enable)

 ## Use the Hotspot garbage-first collector.
 #-XX:+UseG1GC
 #
 ## Have the JVM do less remembered set work during STW, instead
 ## preferring concurrent GC. Reduces p99.9 latency.
 #-XX:G1RSetUpdatingPauseTimePercent=5
 #
 ## Main G1GC tunable: lowering the pause target will lower throughput and vise versa.
 ## 200ms is the JVM default and lowest viable setting
 ## 1000ms increases throughput. Keep it smaller than the timeouts in cassandra.yaml.
 #-XX:MaxGCPauseMillis=500

 ## Optional G1 Settings

 # Save CPU time on large (>= 16GB) heaps by delaying region scanning
 # until the heap is 70% full. The default in Hotspot 8u40 is 40%.
 #-XX:InitiatingHeapOccupancyPercent=70

 # For systems with > 8 cores, the default ParallelGCThreads is 5/8 the number of logical cores.
 # Otherwise equal to the number of cores when 8 or less.
 # Machines with > 10 cores should try setting these to <= full cores.
 #-XX:ParallelGCThreads=16
 # By default, ConcGCThreads is 1/4 of ParallelGCThreads.
 # Setting both to the same value can reduce STW durations.
 #-XX:ConcGCThreads=16

 ### GC logging options -- uncomment to enable

 -XX:+PrintGCDetails
 -XX:+PrintGCDateStamps
 -XX:+PrintHeapAtGC
 -XX:+PrintTenuringDistribution
 -XX:+PrintGCApplicationStoppedTime
 -XX:+PrintPromotionFailure
 #-XX:PrintFLSStatistics=1
 #-Xloggc:/var/log/cassandra/gc.log
 -XX:+UseGCLogFileRotation
 -XX:NumberOfGCLogFiles=10
 -XX:GCLogFileSize=10M
	###########################################################################
	# jvm.options #
	# #
	# - all flags defined here will be used by cassandra to startup the JVM #
	# - one flag should be specified per line #
	# - lines that do not start with '-' will be ignored #
	# - only static flags are accepted (no variables or parameters) #
	# - dynamic flags will be appended to these on cassandra-env #
	###########################################################################

	######################
	# STARTUP PARAMETERS #
	######################

	# Uncomment any of the following properties to enable specific startup parameters

	# In a multi-instance deployment, multiple Cassandra instances will independently assume that all
	# CPU processors are available to it. This setting allows you to specify a smaller set of processors
	# and perhaps have affinity.
	#-Dcassandra.available_processors=number_of_processors

	# The directory location of the cassandra.yaml file.
	#-Dcassandra.config=directory

	# Sets the initial partitioner token for a node the first time the node is started.
	#-Dcassandra.initial_token=token

	# Set to false to start Cassandra on a node but not have the node join the cluster.
	#-Dcassandra.join_ring=true\|false

	# Set to false to clear all gossip state for the node on restart. Use when you have changed node
	# information in cassandra.yaml (such as listen_address).
	#-Dcassandra.load_ring_state=true\|false

	# Enable pluggable metrics reporter. See Pluggable metrics reporting in Cassandra 2.0.2.
	#-Dcassandra.metricsReporterConfigFile=file

	# Set the port on which the CQL native transport listens for clients. (Default: 9042)
	#-Dcassandra.native_transport_port=port

	# Overrides the partitioner. (Default: org.apache.cassandra.dht.Murmur3Partitioner)
	#-Dcassandra.partitioner=partitioner

	# To replace a node that has died, restart a new node in its place specifying the address of the
	# dead node. The new node must not have any data in its data directory, that is, it must be in the
	# same state as before bootstrapping.
	#-Dcassandra.replace_address=listen_address or broadcast_address of dead node

	# Allow restoring specific tables from an archived commit log.
	#-Dcassandra.replayList=table

	# Allows overriding of the default RING_DELAY (1000ms), which is the amount of time a node waits
	# before joining the ring.
	#-Dcassandra.ring_delay_ms=ms

	# Set the port for the Thrift RPC service, which is used for client connections. (Default: 9160)
	#-Dcassandra.rpc_port=port

	# Set the SSL port for encrypted communication. (Default: 7001)
	#-Dcassandra.ssl_storage_port=port

	# Enable or disable the native transport server. See start_native_transport in cassandra.yaml.
	# cassandra.start_native_transport=true\|false

	# Enable or disable the Thrift RPC server. (Default: true)
	#-Dcassandra.start_rpc=true/false

	# Set the port for inter-node communication. (Default: 7000)
	#-Dcassandra.storage_port=port

	# Set the default location for the trigger JARs. (Default: conf/triggers)
	#-Dcassandra.triggers_dir=directory

	# For testing new compaction and compression strategies. It allows you to experiment with different
	# strategies and benchmark write performance differences without affecting the production workload.
	#-Dcassandra.write_survey=true

	# To disable configuration via JMX of auth caches (such as those for credentials, permissions and
	# roles). This will mean those config options can only be set (persistently) in cassandra.yaml
	# and will require a restart for new values to take effect.
	#-Dcassandra.disable_auth_caches_remote_configuration=true

	########################
	# GENERAL JVM SETTINGS #
	########################

	# enable assertions. disabling this in production will give a modest
	# performance benefit (around 5%).
	-ea

	# enable thread priorities, primarily so we can give periodic tasks
	# a lower priority to avoid interfering with client workload
	-XX:+UseThreadPriorities

	# allows lowering thread priority without being root on linux - probably
	# not necessary on Windows but doesn't harm anything.
	# see http://tech.stolsvik.com/2010/01/linux-java-thread-priorities-workar
	-XX:ThreadPriorityPolicy=42

	# Enable heap-dump if there's an OOM
	-XX:+HeapDumpOnOutOfMemoryError

	# Per-thread stack size.
	-Xss256k

	# Larger interned string table, for gossip's benefit (CASSANDRA-6410)
	-XX:StringTableSize=1000003

	# Make sure all memory is faulted and zeroed on startup.
	# This helps prevent soft faults in containers and makes
	# transparent hugepage allocation more effective.
	-XX:+AlwaysPreTouch

	# Disable biased locking as it does not benefit Cassandra.
	-XX:-UseBiasedLocking

	# Enable thread-local allocation blocks and allow the JVM to automatically
	# resize them at runtime.
	-XX:+UseTLAB
	-XX:+ResizeTLAB

	# http://www.evanjones.ca/jvm-mmap-pause.html
	-XX:+PerfDisableSharedMem

	# Prefer binding to IPv4 network intefaces (when net.ipv6.bindv6only=1). See
	# http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6342561 (short version:
	# comment out this entry to enable IPv6 support).
	-Djava.net.preferIPv4Stack=true

	### Debug options

	# uncomment to enable flight recorder
	#-XX:+UnlockCommercialFeatures
	#-XX:+FlightRecorder

	# uncomment to have Cassandra JVM listen for remote debuggers/profilers on port 1414
	#-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=1414

	# uncomment to have Cassandra JVM log internal method compilation (developers only)
	#-XX:+UnlockDiagnosticVMOptions
	#-XX:+LogCompilation

	#################
	# HEAP SETTINGS #
	#################

	# Heap size is automatically calculated by cassandra-env based on this
	# formula: max(min(1/2 ram, 1024MB), min(1/4 ram, 8GB))
	# That is:
	# - calculate 1/2 ram and cap to 1024MB
	# - calculate 1/4 ram and cap to 8192MB
	# - pick the max
	#
	# For production use you may wish to adjust this for your environment.
	# If that's the case, uncomment the -Xmx and Xms options below to override the
	# automatic calculation of JVM heap memory.
	#
	# It is recommended to set min (-Xms) and max (-Xmx) heap sizes to
	# the same value to avoid stop-the-world GC pauses during resize, and
	# so that we can lock the heap in memory on startup to prevent any
	# of it from being swapped out.
	#-Xms4G
	#-Xmx4G

	# Young generation size is automatically calculated by cassandra-env
	# based on this formula: min(100 * num_cores, 1/4 * heap size)
	#
	# The main trade-off for the young generation is that the larger it
	# is, the longer GC pause times will be. The shorter it is, the more
	# expensive GC will be (usually).
	#
	# It is not recommended to set the young generation size if using the
	# G1 GC, since that will override the target pause-time goal.
	# More info: http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html
	#
	# The example below assumes a modern 8-core+ machine for decent
	# times. If in doubt, and if you do not particularly want to tweak, go
	# 100 MB per physical CPU core.
	#-Xmn800M

	#################
	# GC SETTINGS #
	#################

	### CMS Settings

	-XX:+UseParNewGC
	-XX:+UseConcMarkSweepGC
	-XX:+CMSParallelRemarkEnabled
	-XX:SurvivorRatio=8
	-XX:MaxTenuringThreshold=1
	-XX:CMSInitiatingOccupancyFraction=75
	-XX:+UseCMSInitiatingOccupancyOnly
	-XX:CMSWaitDuration=10000
	-XX:+CMSParallelInitialMarkEnabled
	-XX:+CMSEdenChunksRecordAlways
	# some JVMs will fill up their heap when accessed via JMX, see CASSANDRA-6541
	-XX:+CMSClassUnloadingEnabled

	### G1 Settings (experimental, comment previous section and uncomment section below to enable)

	## Use the Hotspot garbage-first collector.
	#-XX:+UseG1GC
	#
	## Have the JVM do less remembered set work during STW, instead
	## preferring concurrent GC. Reduces p99.9 latency.
	#-XX:G1RSetUpdatingPauseTimePercent=5
	#
	## Main G1GC tunable: lowering the pause target will lower throughput and vise versa.
	## 200ms is the JVM default and lowest viable setting
	## 1000ms increases throughput. Keep it smaller than the timeouts in cassandra.yaml.
	#-XX:MaxGCPauseMillis=500

	## Optional G1 Settings

	# Save CPU time on large (>= 16GB) heaps by delaying region scanning
	# until the heap is 70% full. The default in Hotspot 8u40 is 40%.
	#-XX:InitiatingHeapOccupancyPercent=70

	# For systems with > 8 cores, the default ParallelGCThreads is 5/8 the number of logical cores.
	# Otherwise equal to the number of cores when 8 or less.
	# Machines with > 10 cores should try setting these to <= full cores.
	#-XX:ParallelGCThreads=16
	# By default, ConcGCThreads is 1/4 of ParallelGCThreads.
	# Setting both to the same value can reduce STW durations.
	#-XX:ConcGCThreads=16

	### GC logging options -- uncomment to enable

	-XX:+PrintGCDetails
	-XX:+PrintGCDateStamps
	-XX:+PrintHeapAtGC
	-XX:+PrintTenuringDistribution
	-XX:+PrintGCApplicationStoppedTime
	-XX:+PrintPromotionFailure
	#-XX:PrintFLSStatistics=1
	#-Xloggc:/var/log/cassandra/gc.log
	-XX:+UseGCLogFileRotation
	-XX:NumberOfGCLogFiles=10
	-XX:GCLogFileSize=10M