Patent ID: 7111138

Claim:
A storage system comprising a first storage control device and a second storage control device connected so as to be capable of communicating with each other and executing data processing according to a request from a host device, wherein the first storage control device comprises: first control means for judging whether or not the second storage control device can execute a predetermined data processing function relating to a first request received from the host device and, only after said first control means judges that the second control device can execute said predetermined data processing function, said first control means generates a second request corresponding to the first request for taking over said predetermined data processing function by the second storage control device and transmits it to the second storage control device, wherein the second storage control device comprises: second control means for executing the predetermined data processing function based on the second request received from the first storage control device such that the second storage control device takes over said predetermined data processing function relating to a first request from the first storage control device, wherein said predetermined data processing function includes direct backup, internal copying process between a pair of volumes, mirroring, or remote copying, and wherein the first storage control device provides a second storage area controlled by the second storage control device to the host device virtually as a first storage area under control of its own, and the first request requests the data processing relating to the first storage area.