External storage system

摘要

An external storage system has a storage unit for storing data and a plurality of storage controllers for controlling data transfer between an upper level system and the storage unit. Each storage controller has a data buffer for temporarily storing data and a controller for controlling the operation of the storage controller. The external storage system has a management memory for storing management information of the plurality of storage controllers each of which accesses this memory to monitor the operation states of other storage controllers. The external storage system has a first storage controller for processing an input-output request from the upper level system and a second storage controller for standing by for backup for a failed storage controller. In accordance with load distribution information stored in the management memory, the process to be executed by the first storage controller is partially executed by the second storage controller to improve the performance of the whole external storage system.