Patent ID: 7853767

Claim:
A computer system, comprising: one or more first storage systems; one or more second storage systems; one or more host computers coupled to the first storage system and to the second storage system through a network; and a management computer capable of accessing the first storage system, the second storage system, and the host computers, wherein: the first storage system includes: a first interface coupled to the network; a first processor coupled to the first interface, a first memory coupled to the first processor; and a first disk drive for storing data requested to be written by the host computer; the first storage system sets a storage area of the first disk drive as one or more first volume; the first storage system misrepresents an identifier of the storage system and an identifier of the first volume to the host computer; the first storage system provides the set first volume to the host computer, the second storage system includes: a second interface coupled to the network; a second processor coupled to the second interface; a second memory coupled to the second processor; and a second disk drive for storing data requested to be written by the host computer; the second storage system sets a storage area of the second disk drive as one or more second volume; the second storage system misrepresents an identifier of the storage system and an identifier of the second volume as being identical to those misrepresented by the first storage system to the host computer; the second storage system provides the set second volume to the host computer; the management computer includes: a third interface externally coupled; a third processor coupled to the third interface; and a third memory coupled to the third processor; the host computer includes: a fourth interface coupled to the network; a fourth processor coupled to the fourth interface; and a fourth memory coupled to the fourth processor; the first processor copies data stored in the first volume into the second volume; the second processor copies data stored in the second volume into the first volume; the third processor, upon detection of one of a failure in an access from the host computer to the first volume and a failure in an access from the host computer to the second volume: acquires a status of copying between the first volume and the second volume and a status of the first volume from the first processor through the third interface; acquires a status of copying between the first volume and the second volume and a status of the second volume from the second processor through the third interface; and refers to the plurality of acquired statuses to control the access from the host computer to the first volume and the access from the host computer to the second volume.