A first storage control device is provided with a virtual LU for showing a logical volume possessed by a second storage control device as if it were its own volume. When data processing requested from a host device is, for example, a specific processing of large load (such as direct backup, logical volume copy, and so on), whether or not the requested processing can be executed by the second storage control device is judged. When it is executable, a command is transmitted to the second storage control device to make it take over the processing.