You can configure a Flash Pool aggregate by adding one or more allocation units from an SSD storage pool to an existing HDD aggregate.
Any allocation unit from the storage pool that you want to use must be owned by the same node that owns the Flash Pool aggregate.
You add cache to the aggregate by allocation units. You can increase the size of the allocation units later by adding SSDs to the storage pool if there is room.
After you add a cache to the aggregate from SSD storage pools, you cannot change the RAID type of the cache RAID groups.
You can see the amount of cache that will be added to the total cache size by using the storage pool show command.
If you want the RAID type of the cache to different from that of the HDD RAID groups, you must specify the cache RAID type when you add the SSD capacity. After you add the SSD capacity to the aggregate, you can no longer change the RAID type of the cache.
After you add an SSD cache to an aggregate to create a Flash Pool aggregate, you cannot remove the SSD cache to convert the aggregate back to its original configuration.