Patent ID: 7133966

Claim:
A disk array device for storing data in response to communications from a host device, the disk array device comprising: a disk array control unit which performs control of the entire disk array device; a host side data transfer control unit which controls data transfer to and from the host device; a disk array including at least a plurality of data disk drives which constitute one parity group and one or more spare disk drives, wherein the one parity group has a large number of data stripes which are formed over storage areas of the plural data disk drives and the large number of data stripes can be partitioned into two or more sets of the data stripes; a cache memory which is used for temporary storage of data to be transferred between the host device and the disk array; and a subordinate side transfer control unit which controls data transfer to and from the disk array, wherein the disk array control unit comprises: a prediction section which predicts the likelihood of occurrence of a failure for each data disk drive, a disk drive resource information table which includes for each data disk drive information indicating a status of said data disk drive and information of a rate of occurrence of errors in said data disk drive, a spare disk drive resource information table which includes for each spare disk drive information indicating a status of said spare disk drive and information regarding storage areas of said spare disk drive used for recovery with respect to a corresponding data disk drive, wherein said prediction section predicts the likelihood of occurrence of a failure based on information contained in said disk drive resource information table, and a divided data copy section which, in response to a prediction that occurrence of a failure is likely to occur with respect to a data disk drive, and based on information contain in said spare disk drive resource information table, selects two or more data disk drives out of the plural data disk drives as objects of divided data copy, selects two or more divided storage areas by selecting one divided storage area from each of the selected two or more data disk drives, the selected two or more divided storage areas belonging to different sets of the data stripes in the parity group, and controls the subordinate side transfer control unit and the cache memory so as to copy data in the selected two or more divided storage areas to the one or more spare disk drives.