Patent ID: 7908503
Filing Date: 2011-03-15
Classification: G06F,Y02D

Abstract:
1. A method of saving power consumed by a storage system that is connected to a host computer via a network, wherein the storage system has a disk device for storing data based upon a request by the host computer, and plural controllers including at least a first controller and a second controller, each of which controls access to the disk device, wherein the controllers each have an interface connected to the network, a processor connected to the interface, and a memory connected to the processor, wherein the memory stores controller count control information, which indicates the association between the load of the storage system and the count of operating controllers, wherein the host computer recognizes a storage area of the disk device on a logical storage area basis, the storage area including a first logical unit accessed by the first controller and a second logical unit accessed by the second controller, wherein one of the processors measures a load of the storage system, wherein the one of the processors controls power to the controllers in accordance with the measured load of the storage system, wherein, based on the controller count control information and the measured load of the storage system, the one of the processors determines the number of controllers that are to be put into operation, wherein the one of the processors controls power to the controllers in a manner that puts the determined number of controllers into operation, and wherein, prior to turning off power to the first controller, the one of the processors allocates the first logical unit allocated to the first controller to the second controller.