Patent ID: 8566525

Claim:
A method for limiting an amount of write data stored in a cache memory of a storage controller, the method comprising: determining a usable region of a non-volatile storage (NVS) of the storage controller; determining an amount of write data in a current write request for the cache memory; determining a failure boundary associated with the current write request; maintaining a count of write data associated with the failure boundary; and rejecting the current write request for the cache memory when a sum of the count of the write data associated with the failure boundary and the write data in the current write request exceeds a determined percentage of the usable region of the NVS, wherein loss of access to a given failure boundary causes write data associated with the given failure boundary to be held as pinned data until the given failure boundary can be repaired, allowing the pinned data to become unpinned, or until the given failure boundary is determined to have failed, allowing the pinned data to be deleted.