Patent ID: 8234467

Claim:
A storage management device used in a storage system, which stores data in a plurality of storage devices interconnected via a network in a distributed manner, for managing the storage device, the storage management device comprising: a management unit managing one of the storage devices assigned thereto and temporary storage unit assigned thereto, and a control unit for controlling the storage system by managing the storage management device; the management unit comprising: a backup unit, when the data is written into the storage device, storing the data in the previously assigned temporary storage unit before the writing of the data into the storage device is completed; and a take-over unit, when data which is already stored in the temporary storage unit, but which is not yet written into the storage device exists at timing the storage device and the temporary storage unit are assigned, writing the not-yet-written data into the storage device, the control unit comprising: a failure detection unit detecting a failure of one of the plurality of storage devices and the temporary storage unit; and an assignment unit assigning the storage device and the temporary storage to the management unit, wherein when a failure is detected by the failure detection unit, the assignment unit assigns the storage device and the temporary storage unit which caused the failure to another management unit, and assigns another storage device and another temporary storage unit to the management unit, and wherein when the data which is already stored in the temporary storage unit, but which is not yet written into the storage device exists at timing the storage device and the temporary storage unit are assigned by the storage system control device, the take-over unit writes the not-yet-written data into the storage device.