Patent ID: 9026732
Filing Date: 2015-05-05
Classification: G06F

Abstract:
1. A method for managing data in a cache system comprising a first cache, a second cache, and a storage system, comprising: determining a track to demote from the first cache to the second cache comprising a partial track that includes data for less than all sectors of the track, wherein the track in the first cache corresponds to a track in the storage system and is comprised of a plurality of sectors; determining whether the second cache includes a stale version of the track being demoted from the first cache; in response to determining that the second cache includes the stale version of the track, determining whether the stale version of the track includes data for track sectors of the track being demoted from the first cache that do not include data; combining the data for the sectors from the track demoted from the first cache with the data for the track sectors from the stale version that includes data for the track sectors in the track being demoted from the first cache that do not include data into a first new version of the track; writing the first new version of the track to the second cache; and writing the track being demoted from the first cache to a second new version of the track in the second cache in response to determining that the second cache does not include the stale version, wherein the second new version of the track has data of the partial track in non-empty sectors and includes empty sectors to include data for less than all the sectors of the track.