Patent ID: 8521954

Claim:
A management computer which is mutually connected, via a network, to a plurality of storage apparatuses including a real volume, and a host computer which requests writing of data to the plurality of storage apparatuses, wherein, by associating a virtual volume provided to the host computer with a real volume of an other storage apparatus other than the plurality of storage apparatuses, the plurality of storage apparatuses manage the real volume of the other storage apparatus as the real volume of the plurality of storage apparatuses, the management computer comprising: a detection unit configured to detect a correspondence relationship between a virtual volume of one storage apparatus among the plurality of storage apparatuses and a real volume of the one storage apparatus or of the other storage apparatus; and a modification unit which, if the real volume is added to any of the plurality of the storage apparatuses, is configured to modify the correspondence relationship between the virtual volume and the real volume associated with the virtual volume, according to the correspondence relationship detected by the detection unit; wherein the detection unit is configured to detect, from the virtual volume of the one storage apparatus, a number of storage apparatuses up to and including the real volume of other storage apparatuses associated with the virtual volume.