Patent ID: 8037265

Claim:
A storage system comprising: a virtualization apparatus having: an actual volume for storing data sent from a host apparatus, formed in a storage area provided by a physical disk; a virtual volume paired with the actual volume, for storing replicated data for the data; and a work virtual volume for storing the replicated data when it has been copied back for restoration; and an external storage apparatus having: a logical volume that functions as an actual storage area for the virtual volume; a storage tape associated with the logical volume, for storing the replicated data; and a work logical volume associated with the work virtual volume, wherein the external storage apparatus has: a controller for controlling: first processing for making a backup of the replicated data in the logical volume on the tape, and second processing for copying the replicated data backup in the tape to the work logical volume for restoration; a switch for executing data transfer between the logical volume or the work logical volume and the tape, via switching between a plurality of paths; a first table for managing a current data traffic of each of the paths; and a second table for managing a data traffic when a backup of the replicated data in the logical volume was previously made in the tape, the work virtual volume and the work logical volume are configured to recognize an operating system installed in the host apparatus, and when executing the first processing, the controller: checks that data transfer is not being executed for a RAID group including a backup target logical volume; adds the data traffic in the second table to the data traffic in the first table, and specifies, from among the paths, a path whose data traffic resulting from the addition does not exceed a maximum traffic, as a path for data transfer; transfers the replicated data from the backup target volume to the tape, via the path for data transfer; and when executing the second processing, realizes file-based restoration by filed-based copying the replicated data in the tape to the work logical volume for restoration.