21.4. Memory

Red Hat Gluster Storage does not consume significant compute resources from the storage nodes themselves. However, read intensive workloads can benefit greatly from additional RAM.

21.4.1. Virtual Memory Parameters

The data written by the applications is aggregated in the operating system page cache before being flushed to the disk. The aggregation and writeback of dirty data is governed by the Virtual Memory parameters. The following parameters may have a significant performance impact:
  • vm.dirty_ratio
  • vm.dirty_background_ratio
The appropriate values of these parameters vary with the type of workload:
  • Large-file sequential I/O workloads benefit from higher values for these parameters.
  • For small-file and random I/O workloads it is recommended to keep these parameter values low.
The Red Hat Gluster Storage tuned profiles set the values for these parameters appropriately. Hence, it is important to select and activate the appropriate Red Hat Gluster Storage profile based on the workload.