Patent ID: 7219166

Claim:
A storage system comprising: a channel unit that transfers data sent from an upper-level system and transfers data to said upper-level system; a plurality of cache units which are coupled to said channel unit and in which data sent from said channel unit is stored; a control unit that is coupled to said cache units, and transfers or receives data to or from said cache units; at least one first processor controlling transfer of data between said channel unit and said plurality of cache units; at least one second processor controlling transfer of data between said control unit and said plurality of cache units; a disk device in which data sent from said control unit is stored; and a plurality of paths coupling said channel unit to said plurality of cache units, a first one of said paths coupling said channel unit to a first one of said cache units, a second one of said paths coupling said channel unit to a second one of said cache units, and a third one of said paths coupling said first one of said cache units to said control unit, wherein said first one of said paths has no overlap with said second one of said paths.