Patent ID: 7620794

Claim:
A storage system having a plurality of storage apparatuses, each of said plurality of storage apparatuses comprising: a plurality of channel adapters for receiving access commands from a plurality of host computers via network; a plurality of disk devices with which said plurality of storage apparatuses provide control units which are virtual storage areas to the host computer; a plurality of disk adapters for controlling said plurality of disk devices; and a memory for storing information, wherein said plurality of storage apparatuses are connected to each other via a physical switch, and each of said plurality of storage apparatuses provides a virtual switch, wherein said information relates each of identifiers of said control units to each of identifiers of said plurality of storage apparatuses, and relates each of identifiers of the storage apparatuses to each of identifiers of ports of said physical switch or said virtual switch, said information stored in a first memory of a first storage apparatus relates an identifier of a second control unit provided by a second storage apparatus to an identifier of said second storage apparatus, an identifier of said second storage apparatus to an identifier of a second port of said physical switch, said second port is one of a plurality of ports of said physical switch and connected to said second storage apparatus, wherein if said first storage apparatus receives a first access command including an identifier of a first port of a first virtual switch provided by said first storage apparatus and an identifier of a first control unit provided by said first storage apparatus, from said host computer, a first channel adapter in said first storage apparatus sends said first access command to a first disk adapter of said first storage apparatus, based on said identifier of said first control unit included in said first access command and said information, wherein if said first storage apparatus receives a second access command including said identifier of said first port of said first virtual switch and said identifier of said second control unit from said host computer, said first channel adapter changes said identifier of said first port of said first virtual switch to said identifier of a second port of said physical switch, based on an identifier of said second control unit included in said second access command and said information, and sends said changed second access command to said second storage apparatus via said physical switch, and wherein said identifier of said first control unit, said identifier of second control unit, said identifier of said first port of said first virtual switch, and said identifier of said second port of said physical switch are uniquely identified within the storage system.