Patent ID: 7975113

Claim:
A storage system, comprising: an interface coupled to a computer; a plurality of disk drives, including a first plurality of disk drives and a second plurality of disk drives, said first plurality of disk drives configuring a first logical volume, said second plurality of disk drives configuring a second logical volume; and a control unit, coupled to the interface and the plurality of disk drives, providing for the computer a plurality of virtual volumes, wherein said storage system has a first mapping in which a first one of said plurality of virtual volumes is mapped to said first logical volume, and a second mapping in which said first one of said plurality of virtual volumes is mapped to said second logical volume, wherein after said interface receives a command for accessing said first virtual volume from the computer, said control unit converts the command for accessing said first virtual volume into a second command for accessing said first logical volume in said first mapping, and said control unit converts the command for accessing said first virtual volume into a third command for accessing said second logical volume in said second mapping, and wherein, when said storage system receives a command for changing a status of said storage system between said first mapping and said second mapping from said computer, said control unit changes the status of said storage system between said first mapping and said second mapping, and changes a condition of each spindle motor of said first plurality of disk drives and said second plurality of disk drives according to said changing a status of said storage system between said first mapping and said second mapping, and wherein said second logical volume stores different content from that of said first logical volume.