| commit | 5404c40472398d76d3d755254c4ccf53483972a0 | [log] [tgz] |
|---|---|---|
| author | Yingchun Lai <laiyingchun@apache.org> | Fri May 26 14:16:07 2023 +0800 |
| committer | GitHub <noreply@github.com> | Fri May 26 14:16:07 2023 +0800 |
| tree | 5409dac20ed0b458a752e8bd1bf52c89c9ef58b6 | |
| parent | d5f225967aa4575a4670f48dc1bd7dcd5d07ea9e [diff] |
refactor: update replica's dir_node status (part1) (#1487) https://github.com/apache/incubator-pegasus/issues/1383 In prior implemention, every replica has a "dir_node status", if a dir_node has some abnormal status (e.g. in space insufficient), we have to update all replicas' referenced "dir_node status", it is implemented in `replica_stub::update_disks_status`. This make the "dir_node status" updating path too long, and a bit of duplicate. A new implemention is completed in https://github.com/apache/incubator-pegasus/pull/1473, every replica has a reference of dir_node directly, so it would be easy to update replcia's "dir_node status" by updating the referenced dir_node's status once. Before the new implemention, this patch submit a minor refactor to remove `replica_stub::update_disks_status` and related functions and variables. Also some unit tests have been updated.
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Apache Pegasus is a distributed key-value storage system which is designed to be:
Pegasus targets to fill the gap between Redis and HBase. As the former is in-memory, low latency, but does not provide a strong-consistency guarantee. And unlike the latter, Pegasus is entirely written in C++ and its write-path relies merely on the local filesystem.
Apart from the performance requirements, we also need a storage system to ensure multiple-level data safety and support fast data migration between data centers, automatic load balancing, and online partition split.
Persistence of data: Each write is replicated three-way to different ReplicaServers before responding to the client. Using PacificA protocol, Pegasus has the ability for strong consistent replication and membership changes.
Automatic load balancing over ReplicaServers: Load balancing is a builtin function of MetaServer, which manages the distribution of replicas. When the cluster is in an inbalance state, the administrator can invoke a simple rebalance command that automatically schedules the replica migration.
Cold Backup: Pegasus supports an extensible backup and restore mechanism to ensure data safety. The location of snapshot could be a distributed filesystem like HDFS or local filesystem. The snapshot storing in the filesystem can be further used for analysis based on pegasus-spark.
Eventually-consistent intra-datacenter replication: This is a feature we called duplication. It allows a change made in the local cluster accesible after a short time period by the remote cluster. It help achieving higher availability of your service and gaining better performance by accessing only local cluster.
See our documentation on the Pegasus Website.
Pegasus has support for several languages:
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Test tools:
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