Patent ID: 8825953
Filing Date: 2014-09-02
Classification: G06F

Abstract:
1. A computer program product for managing data in a 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, the computer program product comprising a computer readable storage medium having computer readable program code embodied therein that executes to perform operations, the operations 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; 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 into one stride; and copying data from the valid tracks from at least two source strides in the second cache to the target stride.