Patent ID: 6871255

Claim:
A system for storing data comprising: a first storage system comprising a first disk controller and at least one first disk coupled to said first disk controller; a second storage system comprising a second disk controller and at least one second disk coupled to said second disk controller; and a controller coupled to said first storage system, said second storage system, a host computer, and a service processor; wherein said controller comprises a memory in which correlation information among first disk identification information, identification information designating a storage system, and second disk identification information is stored, and said correlation information is set in said controller by said service processor coupled to said controller, and wherein said controller is configured to receive a write request from said host computer, select a storage system including a target disk designated by first disk identification information included in the write request by using said correlation information, obtain identification information designating a selected storage system and second disk identification information designating the target disk based on said first disk identification information included in the write request and said correlation information, and send a write request to the selected storage system according to said identification information designating the selected storage system and said second disk identification information.