The Flash Pool technology has some configuration requirements that you should be aware of before planning to use it in your storage architecture.
Flash Pool aggregates cannot be used in the following configurations:
You can use Flash Pool aggregates and the Flash Cache module (WAFL external cache) in the same system. However, data stored in a Flash Pool aggregate is not cached in the Flash Cache module. Flash Cache is reserved for data stored in aggregates composed of only HDDs. For more information about Flash Cache and WAFL external cache, see the Data ONTAP System Administration Guide for 7-Mode.
You can use data compression on volumes associated with a Flash Pool aggregate. However, compressed blocks are not cached in the Flash Pool cache for either read or write operations.
FlexShare is not supported for volumes associated with Flash Pool aggregates.
Read-only volumes, such as SnapMirror or SnapVault destinations, are not cached in the Flash Pool cache.
If the Flash Pool aggregate is not mirrored and it is not used for a MetroCluster configuration, you should disable automatic aggregate Snapshot creation for the Flash Pool (aggr options nosnap command). For information about automatic aggregate Snapshot copy creation, see the Data ONTAP System Administration Guide for 7-Mode.
Flash Pool aggregates can be created from mirrored aggregates; however, the SSD configuration must be kept the same for both plexes.
For a list of the platforms that support Flash Pool aggregates, and for minimum numbers of SSDs, see the Hardware Universe.
If you create a Flash Pool aggregate using an aggregate that was created using Data ONTAP 7.1 or earlier, the volumes associated with that Flash Pool aggregate will not support write caching.
For more information about the types of workloads that benefit from using Flash Pool aggregates, see Technical Report 4070: NetApp Flash Pool Design and Implementation Guide.