Patent ID: 7124169

Claim:
A network system comprising: a computer; a switch that is coupled to said computer via a network; a first storage device that is coupled to said switch via the network, said first storage device storing first data; and a second storage device that is coupled to said switch via the network; wherein said computer issues a first read request for the data stored in said first storage device; wherein when said switch receives said first read request, if said second storage device has second data that is copy data of said first data, said switch converts said first read request into a second read request for said second data, and transmits said second read request to said second storage device via the network, wherein if said second storage device does not have said second data, said switch transmits said first read request to said first storage device via the network; wherein when receiving the data, said switch transfers the received data to said computer as said first data from said first storage devices; wherein said first storage device includes a plurality of addressable storage areas for storing said first data, while said second storage device includes a plurality of addressable storage areas for storing said second data; wherein said first read request includes a first destination address where said first data resides; wherein said switch has information of whether or not said second storage device has said second data; and wherein if said second storage device has said second data, said switch changes said first destination address to a second destination address, where said second data resides, to be incorporated into said second read request.