Patent ID: 7502955

Claim:
A disk array system comprising: a plurality of data disks providing one or more RAID (redundant array of independent disks) groups; one or more spare disks; a controller that controls data input and output to and from the data disks and the spare disks; a RAID configuration management table that registers a correspondence relationship between a logical location and a physical location for each of the data disks in the RAID groups; and a spare disk management table that registers a correspondence relationship between a logical location and a physical location for each of the spare disks, wherein the controller, upon a failure occurring in any of the data disks, performs a correction copy to any of the spare disks from other data disks belonging to the RAID group to which the data disk causing the failure belongs, and updates the RAID configuration management table and the spare disk management table by interchanging the physical location of the spare disk to which the correction copy has been performed and the physical location of the data disk causing the failure.