Patent ID: 8312314

Claim:
A storage system, comprising: a host interface coupled to a host computer; a disk drive which provides a logical device to the host computer; a disk interface coupled to the disk drive; a cache memory; a switch LSI; and a plurality of controllers coupled to the switch LSI; wherein: the host interface, the disk interface, the cache memory, and the switch LSI are coupled to each other; the host interface stores a first routing information which includes an identifier of the logical device and an identifier of the controller in charge of the logical device, and transfers an access request from the host computer to the controller in charge of the logical device by referring to the first routing information; the disk interface stores a second routing information which includes an identifier of the disk drive and an identifier of the controller in charge of the disk drive, and transfers the access request from the disk drive to the controller in charge of the disk drive by referring to the second routing information; the cache memory stores a volume allocation information which includes an identifier of the logical device, an identifier of the disk drive, an identifier of the controller for managing the volume, and an identifier of the controller for failover; and if an error occurs in an error controller which is one of the plurality of controllers, the switch LSI cuts off an I/O path between the error controller and the other devices, and an alternative controller, which receives an error occurrence notice, updates the first routing information and the second information by referring to the volume allocation information.