Patent ID: 7805564

Claim:
A storage system comprising: a first storage system including a plurality of first disk drives and a first controller, said first controller managing a plurality of first logical units provided with said plurality of first disk drives in said first storage system; a second storage system including a plurality of second disk drives and a second controller, said second controller managing a plurality of second logical units provided with said plurality of second disk drives in said second storage system; and a switch, being adapted to be coupled to a host computer, said first storage system and said second storage system, and providing a third logical unit to said host computer, said third logical unit being mapped to both a first logical unit of said plurality of first logical units of said first storage system and a second logical unit of said plurality of second logical units of said second storage system, wherein said third logical unit is displayed as being mapped to both said first storage system and said second storage system on a display of a management computer coupled to said switch, and wherein said switch receives a first command to access said third logical unit from said host computer and sends a second command, corresponding to said first command, to at least one of said first logical unit of said first storage system and said second logical unit of said second storage system.