Patent ID: 7568075

Claim:
A storage system comprising: a plurality of hard disk drive (HDD) devices that store data received from a host computer; a plurality of flash memory devices that store data received from the host computer; and a processing unit that controls WRITE and READ requests received from the host computer to a plurality of logical volumes configured by at least one of the plurality of HDD devices or the plurality of flash memory devices, wherein the processing unit manages a usage status management table that stores usage status information related to endurance of each of the plurality of flash memory devices, and endurance threshold values, wherein the processing unit manages a read/write cycle management table that stores read cycles and write cycles for each of the plurality of logical volumes, wherein the processing unit manages a device type management table that stores information of amount of power consumption per a certain time period of at least one type of HDD devices and a type of the flash memory device, and determines a total amount of power consumption of the plurality of HDD devices in operation and the plurality of flash memory devices in operation based on the device type management table, and wherein, when the processing unit requests to optimize the total amount of power consumption or the endurance of the flash memory devices, the processing unit determines a first device as a source device and a second device as a destination device, which type is different from the first device, based on the usage status management table and the read/write cycle management table, and migrates data from the first device to the second device based on a priority of conditions including the power consumption and the endurance of the flash memory devices.