Patent ID: 8219770

Claim:
A storage system comprising: a virtualization apparatus having a control unit, said control unit setting an actual volume for storing data sent from a host apparatus, formed in a storage area provided by a physical disk; and a virtual volume paired with the actual volume, for storing replicated data for the data; and an external storage apparatus having a logical volume that functions as an actual storage area for the virtual volume; and a tape associated with the logical volume, for storing the replicated data; wherein the external storage apparatus has a copy unit for copying the replicated data stored in the logical volume to the tape; wherein the external storage apparatus comprises a controller unit for controlling backup processing executed between a plurality of the logical volumes and a plurality of the tapes, wherein some or all of the plurality of the logical volumes forms a RAID group, some or all of the plurality of the tapes forms a tape group, and the RAID group and the tape group are associated with each other via a plurality of data transfer paths, and wherein the controller unit: judges whether to execute the backup processing to make a backup of the replicated data stored in a backup target logical volume from among the plurality of logical volumes, in accordance with the data transfer status of the replicated data stored in the RAID group including that backup target logical volume running through the data transfer path, and selects one path from among the plurality of data transfer paths in accordance with the amount of replicated data running through each of the data transfer paths.