Patent ID: 7171522
Filing Date: 2007-01-30
Classification: G06F

Abstract:
1. A storage system having a cluster configuration, comprising: plural storage adaptors each of which is provided with a cache memory that stores read/written data according to an I/O (input/output) request from a host and a device that holds the data stored in the cache memory; means for connecting an external storage having a logical device that handles read/written data and an external cache memory to one of the plural storage adaptors; means for monitoring and for grasping a usage situation of the cache memories of the plural storage adaptors; and selection means for referring to information of the usage situation of the cache memories acquired by the grasping means and for selecting any of the storage adaptors so that usage of the cache memories is equalized, wherein: the logical device of the external storage is controlled by the storage adaptor selected by the selection means via the connection means.