How Flash Pools work

The Flash Pool technology enables you to add one or more RAID groups composed of SSDs to an aggregate that consists of RAID groups of HDDs.

The SSDs provide a high-performance cache for the active data set of the data volumes provisioned on the Flash Pool, which can increase the performance of the volumes associated with the aggregate without requiring the aggregate to be composed entirely of SSDs.

The SSD cache does not contribute to the size of the aggregate as calculated against the maximum aggregate size. For example, even if an aggregate is at the maximum aggregate size, you can add an SSD RAID group to it.

The HDD RAID groups in a Flash Pool behave the same as HDD RAID groups in a standard aggregate, following the same rules for mixing disk types, sizes, speeds, and checksums.

The checksum type, RAID type, and RAID group size values can be configured for the SSD cache RAID groups and HDD RAID groups independently.

There is a platform-dependent maximum size for the SSD cache. For information about this limit for your platform, see the Hardware Universe.