Patent ID: 8332603

Claim:
A computer system comprising: a host computer configured to: store path definition information including a storage ID, a volume ID, and validities of a plurality of paths between the host computer and one of a first storage system or a second storage system identified by the storage ID for accessing a certain volume identified by the volume ID in the one of the first storage system or the second storage system; send an I/O request via the plurality of paths, based on the path definition information; receive information indicating the storage ID and the volume ID; and update the path definition information based on the received information, wherein the first storage system includes a first interface, a first disk drive, and a first controller which provides, via the first interface, a first volume using the first disk drive; wherein the second storage system is coupled to the first storage system, and includes a second interface, a second disk drive, and a second controller which provides, via the second interface, a second volume using the second disk drive, wherein the second controller is configured to copy data of the second volume to the first volume, wherein, during initial copying from the second volume to the first volume, a validity corresponding to a first path between the host computer and the first interface, included in the path definition information, is set to “Invalid” to inhibit access from the host computer to the first interface via the first path and a validity corresponding to a second path between the host computer and the second interface, included in the path definition information, is set to “Valid” to permit access from the host computer to the second interface via the second path, and wherein, after completion of the initial copying, the host computer is configured to change the validity corresponding to the first path included in the path definition information from “Invalid” to “Valid” to permit access from the host computer to the first interface via the first path, while access continues to be permitted between the host computer and the second interface via the second path.