Storage system for sending an access request from a host to a storage subsystem

A storage system comprising:na 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; anda device, 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.

A storage system comprising:na first storage system including a plurality of first disk drives and a first controller, said first controller managing a plurality of first logical units, said plurality of first logical units corresponding to 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, said plurality of second logical units corresponding to said plurality of second disk drives in said second storage system; anda device, 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.

A method for managing a storage system, wherein the storage system comprises a first storage system including a plurality of first disk drives and a first controller, a second storage system including a plurality of second disk drives and a second controller, a device and a management computer, the method comprising:nmanaging, by the first controller, a plurality of first logical units provided with said plurality of first disk drives in said first storage system; andmanaging, by the second controller, a plurality of second logical units provided with said plurality of second disk drives in said second storage system,wherein the device is coupled to a host computer, said first storage system and said second storage system, and provides a third logical unit to said host computer, said third logical unit being mapped to both a first logical unit of said first logical units of said first storage system and a second logical unit of said second logical units of said second storage system.

A device comprising:na plurality of interface parts being coupled to a host computer, a first storage system and a second storage system, wherein said first storage system includes a plurality of first disk drives and a first controller managing a plurality of first logical units provided with said plurality of first disk drives in said first storage system, and wherein said second storage system includes a plurality of second disk drives and a second controller managing a second logical unit provided with said plurality of second disk drives in said second storage system; anda processor performing a control of said device,wherein said device provides 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.