Patent ID: 7886109

Claim:
A storage system coupled to a management server comprising: a processor which controls an Input/Output (I/O) request from a host computer; a plurality of physical devices including a first physical device; and a memory storing status information of the plurality of physical devices, the status information indicating a status of the plurality of the physical devices, wherein the processor changes power supply for the plurality of physical devices, wherein when the power supply for the first physical device is stopped, the processor starts the power supply for the first physical device, and then confirms operation of the first physical device, and then stops the power supply for the first physical device, and wherein if the first physical device has a failure during starting of the power supply, or if the first physical device has an operation error during confirming operation of the first physical device, or if the first physical device has a failure during stopping of the power supply for the first physical device, the processor transmits an error report to the management server, wherein if a failure of the power supply to start, an operation error, or a failure of the power supply to stop for the first physical device occurs, the processor registers the status of the first physical device in the status information as a blocked status, and wherein the blocked status is the status when the first physical device is started, then operation is confirmed through a test I/O, and the first physical device is stopped again.