Patent ID: 7395396

Claim:
A system for storing data comprising: a first storage system including a first controller and a plurality of first logical volumes configured by at least one first physical disk coupled to the first controller; at least one second storage system coupled to the first storage system, wherein the second storage system includes a second controller and a plurality of second logical volumes configured by at least one second physical disk coupled to the second controller; and a management computer coupled to the first storage system, wherein the first storage system manages a plurality of virtual volumes, which are access targets of a host computer, provided by a plurality of logical volumes including the plurality of first logical volumes and the plurality of second logical volumes, and manages a relation between identifiers used by the host computer to access the plurality of virtual volumes to read/write data and information for accessing the plurality of logical volumes providing the plurality of virtual volumes, one or more virtual volumes being provided by one logical volume, wherein the management computer manages a storage class relation between the plurality of virtual volumes and a plurality of storage classes defined based on attributes of the plurality of logical volumes providing the plurality of virtual volumes, wherein the management computer receives information for specifying a source virtual volume and a destination storage class selected from the plurality of storage classes, the source virtual volume being accessed to read/write data by the host computer by using a first identifier, wherein a target virtual volume is selected from virtual volumes related to the destination storage class, wherein data of a source logical volume providing the source virtual volume are migrated to a target logical volume providing the target virtual volume, and wherein the first storage system assigns the first identifier to the target virtual volume instead of the source virtual volume.