A second storage system (SS2) comprises a plurality of tapes, a first storage device capable of performing random access at a rate higher than the tapes, and a virtual storage device emulating the first storage device. A first storage system (SS1) comprises a second storage device and a third storage device that has the virtual storage device mapped therewith. The SS2 reserves a storage space on the first storage device and reads data from the tape corresponding to the virtual storage device into the storage space. The SS1 performs copying between the second storage device and third storage device and, in this process, sends a command for access generated in the third storage device to the virtual storage device. When receiving the Access Command corresponding to the virtual storage device, the SS2 accesses the storage space.