Optimizing a System with Disk Stores

This topic explains how to optimize the availability and performance of a VMware Tanzu GemFire system with disk store.

1. Tanzu GemFire recommends the use of ext4 filesystems when operating on Linux or Solaris platforms. The ext4 filesystem supports preallocation, which benefits disk startup performance. If you are using ext3 filesystems in latency-sensitive environments with high write throughput, you can improve disk startup performance by setting the maxOplogSize (see the DiskStoreFactory.setMaxOplogSize) to a value lower than the default 1 GB and by deactivating preallocation by specifying the system property gemfire.preAllocateDisk=false upon Tanzu GemFire process startup.
2. When you start your system, start all the members that have persistent regions at roughly the same time. Create and use startup scripts for consistency and completeness.
3. Shut down your system using the gfsh shutdown command. This is an ordered shutdown that positions your disk stores for a faster startup.
4. Configure critical usage thresholds (disk-usage-warning-percentage and disk-usage-critical-percentage) for the disk. By default, these are set to 80% for warning and 99% for errors that will shut down the cache.
5. Decide on a file compaction policy and, if needed, develop procedures to monitor your files and execute regular compaction.
6. Decide on a backup strategy for your disk stores and follow it. You can back up a running sytem by using the backup disk-store command.
7. If you remove any persistent region or change its configuration while your disk store is offline, consider synchronizing the regions in your disk stores.

8. By default, the disk stores are recovered in parallel when the cluster restarts. Parallel disk store recovery is usually faster than sequential disk store recovery. If you require sequential disk store recovery, start your servers by setting the system property: geode.parallelDiskStoreRecovery=false. For example, using gfsh to start your servers:

   start server --name=server1 --J=-Dgeode.parallelDiskStoreRecovery=false