A warm cache means that the contents of the cache remain persistent across planned reboots. By default, SmartIO does not provide a warm cache capability for VxVM caches. The cache area metadata is not flushed during a system shut down. The cache is invalidated after the system reboot, and whenever the volumes need to be restarted. This behavior is known as a 'cold' cache.

Symantec does not recommend that you configure a warm cache, because it may lead to data inconsistency. However, in some circumstances, when proper care is taken, it can be beneficial to configure a warm cache. For example, in the case of a controlled, planned reboot you may want to explicitly enable a warm cache. This feature enables you to flush the metadata to the cache, thus creating a warm cache.

If you enable a persistent or warm cache, VxVM detects and invalidates the persistent cache if the data volume was updated while the cache was offline. In clustered environments, if the cache area on a node is persisted during a planned shutdown on that node, and the data volume is updated on another node, the warm cache contents are treated as stale and persisted cached data is evicted.