In the event a CF cache structure fails, DFSMS attempts to rebuild it so that it remains available to the data with which it is associated. A CF cache structure is also rebuilt if DFSMS detects a loss of connectivity or an undersized cache structure.

If the rebuilding process is successful and connectivity resumes as before, all opens that were tied to the CF cache structure that failed are automatically reestablished. If the rebuild process fails, but another CF cache structure is defined in the cache set associated with the storage class and connectivity exists to that CF cache structure, then all opens are automatically reassigned to this alternate CF cache structure.

If the rebuild process fails and no alternate CF cache structure is available, any opens currently using the CF cache structure that failed are marked as broken. DFSMS fails the rebuilding process if the new CF cache structure is smaller than the failed structure, or if it does not have the same connectivity. In those cases where DFSMS cannot rebuild a CF cache structure, the next attempt to open a data set associated with the failed cache structure fails. You might need to redefine the cache structure or correct the connectivity problems.