Patent ID: 8402211

Claim:
A disk array apparatus comprising: a first controller coupled to an information processing apparatus and controlling to transfer/receive data to/from said information processing apparatus and controlling to read/write data; a plurality of first disk drives each coupled to said first controller via a converter, each of first disk drives corresponds to a converter and stores data received via said converter, said converter performing a conversion of an interface between a Fibre Channel (FC) interface and a Serial AT Attachment (Serial ATA) interface; a plurality of second disk drives each coupled directly without a converter to said first controller and storing data sent according to a FC interface; a first Redundant Array of Inexpensive Disks (RAID) group being formed by using said first disk drives; a second RAID group being formed by using said second disk drives; and at least one spare disk drive, wherein said first controller stores data in said spare disk drive and corresponds the stored data in said spare disk to data stored in at least one of said first disk drives, if said first controller performs a first spare process, and wherein said first controller stores data in said spare disk drive and corresponds the stored data in said spare disk to data stored in at least one of said second disk drives, if said first controller performs a second spare process, wherein said first controller also includes a power saving mode execution section which sets a number of said hard disk drives according to the redundancy of said first or second RAID group to a power saving mode, and if time from start of power saving mode exceeds a predetermined value for said first or second RAID group, said power saving mode of said hard disk drives within said first or second RAID group is cancelled.