How cache consistency is achieved
Cache consistency for FlexCache volumes is achieved using three primary techniques: delegations, attribute cache timeouts, and write operation proxy.
- Delegations
You can think of a delegation as a contract between the origin system and the caching volume; as long as the caching volume has the delegation, the file has not changed. Delegations are used only in certain situations.
- Attribute cache timeouts
When data is retrieved from the origin volume, the file that contains that data is considered valid in the FlexCache volume as long as a delegation exists for that file. If no delegation exists, the file is considered valid for a certain length of time, specified by the attribute cache timeout.
- Write operation proxy
If a client modifies a file that is cached, that operation is passed back, or proxied through, to the origin system, and the file is ejected from the cache.
