Patent ID: 7627610

Claim:
A computer system comprising: a first storage system that includes a first logical volume and a first processing unit; a second storage system coupled with the first storage system and that includes a second logical volume, a third logical volume, an arbitration unit, a power supply control unit to control a power supply of a storage device forming said second logical volume, and a second processing unit; and a computer coupled with the first storage system, wherein the computer includes a transmitter that transmits data to the first storage system, wherein the first processing unit records the data transmitted from the computer in the first logical volume and generates update data including the data, wherein the arbitration unit determines whether the update data is received from the first storage system; wherein, if the arbitration unit determines that the update data is received from the first storage system and the storage device which forms the second logical volume is turned off, the arbitration unit transmits an instruction to the power supply control unit to control the power supply to turn on the storage device to thereby activate the second logical volume; wherein the arbitration unit records the update data in the activated second logical volume, wherein the second processing unit reads the update data recorded in the second logical volume and records the read update data in the third logical volume.