AVFS has the ability to define a uniform block of raid protected flash as cache. Caching is managed by AVFS and is file based with folder granularity. One central cache for the system as a whole. This differs from the block level caching which maybe available in each storage array separately.
The file based caching mechanism uses the east-west network internally to copy data between spindles and cache. It can be determined separately for each directory or folder whether caching should be on demand or pinned.
The cache mechanism can also be used bidirectional. Source data from spindles can be copied to the cache and source data stored on the cache can be moved to spindles.