Patent ID: 8086792
Filing Date: 2011-12-27
Classification: G06F

Abstract:
1. A method, comprising: updating a track in a cache in response to a write request; destaging the updated track from the cache to a storage device; setting a verification required flag for the destaged track to indicate that verification is required in response to destaging the updated track from the cache; returning complete to the write request before verifying that the storage device successfully completed writing the destaged track to the storage device; retaining the destaged track in the cache; verifying that the storage device is successfully completing writing data after the track is destaged; indicating, in response to verifying that the storage device is successfully completing the writing of data, destaged tracks eligible for removal from the cache that were destaged before the storage device is verified by setting the verification required flags for the destaged tracks to indicate that verification is not required, wherein the destaged track is not indicated as eligible for removal from the cache until the storage device is verified after the track is destaged to the storage device; initiating a demote operation to demote the retained destaged track in the cache; determining whether the verification required flag for the destaged track to demote indicates that verification is required in response to initiating the demote operation; and demoting the destaged track from the cache in response to determining that the verification required flag indicates that verification is not required for the destaged track.