Patent ID: 7856526

Claim:
A storage system comprising: a first storage apparatus including a plurality of first physical disks and providing a first logical volume configured from said plurality of first physical disks to a host computer; a second storage apparatus including a plurality of second physical disks and providing a second logical volume configured from said plurality of second physical disks to said host computer; and a management server adapted to manage operation of said first storage apparatus and said second storage apparatus; wherein said first storage apparatus includes a first memory, and a first processor; wherein said second storage apparatus includes a second memory, and a second processor; wherein when said first processor receives an instruction, which instructs data migration from said first volume in said first storage apparatus to said second volume in said second storage apparatus, from said management server, said first processor is adapted to read data stored in the first logical volume and send said data to the second storage apparatus, wherein said second processor is adapted to receive said data sent from said first storage apparatus and make access to said second logical volume to store said data, wherein said management server is adapted to obtain information concerning a last access time to said first volume by said host computer, said last access which is a last time of the last access from said host computer to said first logical volume that is a source volume of said data migration, and wherein, if a predetermined time period has elapsed from said last access time without an access to said second volume of said second storage system from said host computer, the management server sends an instruction to the second storage apparatus to switch a state of said plurality of second physical disks configuring said second logical volume from a normal power consumption mode to a power saving mode.