Considerations for adding SSDs to an existing storage pool versus creating a new one

You can increase the size of your SSD cache in two ways—by adding SSDs to an existing SSD storage pool or by creating a new SSD storage pool. The best method for you depends on your configuration and plans for the storage.

The choice between creating a new storage pool or adding storage capacity to an existing one is similar to deciding whether to create a new RAID group or add storage to an existing one:

If your storage pool is providing allocation units to Flash Pool aggregates whose caches have different RAID types, and you expand the size of the storage pool beyond the maximum RAID4 RAID group size, the newly added partitions in the RAID4 allocation units are unused.