International Business Machines Corporation
Variable cache status for selected volumes within a storage system

Abstract:

A method for improving cache hit ratios for selected volumes within a storage system is disclosed. In one embodiment, such a method includes storing, in a cache of a storage system, non-favored storage elements and favored storage elements. The favored storage elements are retained in the cache longer than the non-favored storage elements. The method maintains a "non-favored" LRU list that contains entries associated with non-favored storage elements and designates an order in which the non-favored storage elements are evicted from the cache. The method also maintains one or more "favored" LRU lists that contain entries associated with favored storage elements and designate an order in which the favored storage elements are evicted from the cache. Each "favored" LRU list is associated with favored storage elements that have a different preferred residency time in the cache. A corresponding system and computer program product are also disclosed.