Patent ID: 8127097

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 said one of said first storage system or said 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, said first storage system including 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; said second storage system coupled to the first storage system, including 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 copies data of the second volume to the first volume, wherein, as the received information by the host computer, the first controller misrepresently provides, via the first interface, first information including (1) a certain storage ID as the storage ID of the first storage system, and (2) a certain volume ID as the volume ID of the first volume, and the second controller misrepresently provides, via the second interface, second information including (3) said certain storage ID as the storage ID of the second storage system, and (4) said certain volume ID as the volume ID of the second volume; wherein said host computer is configured to use said certain storage ID as the storage ID in said received information and to use said certain volume ID as the volume ID in said received information.