FAULT RECOVERY METHOD IN A SYSTEM HAVING A PLURALITY OF STORAGE SYSTEMS

System availability is improved in a second storage system, connected to a first storage system, and having means for virtualizing devices within the first storage system as its own devices. When the virtual storage system or a storage management server detects a fault in the virtual storage system, the management server investigates the range affected by the fault, identifies a device for which measures must be taken, determines a transfer target device which accommodates the performance, reliability, and other attributes of the affected device, and issues a device transfer instruction for the virtual storage system. In the virtual storage system, the data of the device specified by the instruction within the virtual storage system is transferred to a device, specified by the management server, within the system itself, or to a device within another virtual storage system.