Patent ID: 7373456

Claim:
A disk array apparatus connected to an information processing apparatus so as to be able to communicate therewith, comprising: a plurality of hard disk drives; a controller constructed by including a host interface which receives a request for a data read and request for a data write from/to said hard disk drives from said information processing apparatus, a disk interface connected to said hard disk drives so as to be able to communicate therewith through a communication path which performs data input/output to/from said hard disk drives, a memory, a CPU which controls said host interface and said disk interface and a time counting mechanism; and 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, wherein a logical volume is formed in a RAID group with redundancy made up of a plurality of said hard disk drives, said disk array apparatus comprising: an access time storage section which stores, upon reception of a request for a data read or request for a data write from/to said logical volume from said information processing apparatus, the time acquired from said time counting mechanism as the access time in said memory in association with an identifier of said RAID group in which said logical volume is formed; and a power saving mode execution section which refers to said access time stored in said memory and sets a number of said hard disk drives according to the redundancy of said RAID group to a power saving mode when the difference between the time acquired from said time counting mechanism and said access time exceeds a predetermined time, wherein said plurality of hard disk drives include (1) a plurality of first disk drives each coupled to both said first controller, each of first disk drives corresponding to a converter and storing 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, (2) a plurality of second disk drives each coupled to said first controller and storing data sent according to a FC interface, and (3) at least one spare disk drive, a first Redundant Array of Inexpensive Disks (RAID) group is formed by using said first disk drives, a second RAID group is formed by using said second disk drives, 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 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.