How Flash Pool aggregates and Flash Cache compare

Both the Flash Pool technology and the family of Flash Cache modules (Flash Cache and Flash Cache 2) provide a high-performance cache to increase storage performance. However, there are differences between the two technologies that you should understand before choosing between them.

You can employ both technologies on the same system. However, data stored in volumes associated with a Flash Pool aggregate (or an SSD aggregate) is not cached by Flash Cache.

Criteria	Flash Pool aggregate	Flash Cache
Scope	A specific aggregate	All aggregates assigned to a node
Caching types supported	Read and write	Read
Cached data availability during and after takeover events	Cached data is available and unaffected by either planned or unplanned takeover events.	Cached data is not available during takeover events. After giveback for a planned takeover, previously cached data that is still valid is re-cached automatically.
PCIe slot on storage controller required?	No	Yes
Supported with array LUNs?	No	Yes

For more information about Flash Cache, see the Clustered Data ONTAP System Administration Guide for Cluster Administrators.For more information about Flash Pool aggregates, see the Clustered Data ONTAP Physical Storage Management Guide.