Geode JVMs use disk in several ways, including:
- Logging and statistics
- Region persistence and overflow
- Gateway queue persistence and overflow
- Client queue overflow
In an active system, these files (especially the region persistence files) can use a lot of disk space.
Disk Store Monitor runs in each JVM and monitors disk usage. For additional details, see the Apache Geode Documentation.
It logs a warning like below in the Geode log file when the disk usage exceeds the usage threshold (default=80%).
It throws errors and warnings like below when the disk usage exceeds the critical threshold (default=99%) and shuts down the JVM.
In conjunction with the
Disk Store Monitor warnings and errors, an IOException with the message Not enough space left on device like below may also be thrown either by a Geode thread or an application thread.
One way to see disk space usage of a given disk is to use the operating system
Another way to determine whether there is a disk issue is to use
vsd to display the disk free space values contained in a given Geode statistics archive.
The chart below shows DiskDirStats volumeFreeSpace values. The DiskDirStats volumeFreeSpace values show the available usable space in the directory. In this case, the disk store ran out of disk space.
There are several actions that can help alleviate disk issues issues, including:
- Remove old Geode log and statistics files
- Compact the Geode region and queue persistence files
- Configure Geode log and statistics rolling so earlier logs and statistics files are deleted
- Add additional disks for region and queue persistence and overflow
For additional details, see the Apache Geode Documentation.