Patent ID: 7849265

Claim:
A storage system comprising: multiple storage control units in communication with each other via a network, each storage control unit including at least one physical port for communication with a first Fibre Channel (FC) switch; at least one first virtual port created on a first one of said physical ports in a first storage control unit of said multiple storage control units; and a first virtual volume created on the first storage control unit, said first virtual volume mapping to a logical volume on an external storage system in communication with said first storage control unit, wherein a computer accesses the first virtual volume via the first virtual port for accessing the logical volume, wherein, when considering whether the first virtual port and said first virtual volume are able to be transferred to another physical port on a second one of said storage control units, a determination is made as to whether direct communication between said multiple storage control units will be required for accessing the logical volume via said first virtual port and said first virtual volume on said second storage control unit, wherein, when the determination indicates that direct communication between said multiple storage control units will be required for accessing the logical volume through said first virtual port and said first virtual volume on said second storage control unit, an alternative storage control unit is located as a target, to which the first virtual port and the first virtual volume are able to be transferred instead of said second storage control unit, so as to avoid direct communication between said storage control units when accessing the logical volume through said first virtual port and said first virtual volume.