Patent ID: 8145930

Claim:
A storage system comprising: a storage subsystem including one or more physical device(s), a storage region composed of at least a portion of the one or more physical device(s), and a power supply control unit for controlling the state of power supply in the physical device(s); a host computer including an assigned storage region assigned from the storage subsystem, and a monitor for acquiring information for management of the assigned storage region; and a management computer including a power supply control indication unit for ordering the power supply control unit to change the power supply state in the physical device(s) to ‘on’ or another state, and a notification unit for notifying the host computer of the shift in the power supply state in the physical device(s), wherein the host computer has a storage region information table that stores first information indicating the power supply state, including whether or not the power supply state in the storage region is ‘on,’ and second information detailing a usage measurement concerning the storage region, and wherein the monitor acquires, when acquiring the information for management of the storage region, the second information detailing the usage measurement from the storage region if the power supply state in the storage region is ‘on,’ or acquires the second information stored in the storage region information table if the power supply state in the storage region is not ‘on’.