Patent ID: 8825956
Filing Date: 2014-09-02
Classification: G06F

Abstract:
1. A method for managing data in a computer readable cache system comprising a first cache, a second cache having multiple storage devices for storing tracks of data, and a storage system comprised of storage devices, comprising: maintaining information on strides configured in the second cache, including information indicating a number of valid tracks in the strides, wherein a stride has at least one of valid tracks and free tracks not including valid data, wherein the strides comprise data strides populated with tracks of data, and wherein the tracks are maintained in the storage system; determining tracks to demote from the first cache; forming a first stride including the determined tracks to demote for a Redundant Array of Independent Disk (RAID) configuration based on a RAID configuration defined for the second cache; striping the first stride of tracks from the first cache across the storage devices of the second cache to form a second stride in the second cache, wherein the first cache stores tracks comprising modified or unmodified data and sequential or non-sequential data, and wherein tracks formed in strides in the first cache to promote to the second cache comprise unmodified non-sequential data; selecting a target stride in the second cache based on a stride most recently used to consolidate strides from at least two strides in the second cache into the target stride; and copying data from the valid tracks from the at least two strides in the second cache to the target stride.