Patent ID: 7334164

Claim:
A method for controlling a storage device that comprises: a storage device part including plural storage media; plural control parts each including a processor and a cache memory, each said processor controlling data writing from a computer to the storage device part and data reading from the storage device part to the computer, and each said cache memory temporarily storing the data; and a management part that detects a failure that occurs in the control parts, wherein communication-capable connection is provided between the storage device part and the control parts, and between the control parts, the method comprising the steps of: when the computer requests data to be written into or read from the storage device, writing the data to a cache memory of an active control part of the control parts, and copying the data from the cache memory of the active control part to a cache memory of a standby control part an writing; and when it is detected by the management part that a failure occurs in one of the active control part and the standby control part, transferring data not yet written to the storage device part of data stored in a cache memory of the other one of the active control part and the standby control part in which the failure does not occur, to a cache memory of a control part other than the active and standby control parts.