Patent ID: 7831781

Claim:
A storage system comprising: a host apparatus; a virtualization apparatus including a storage apparatus and a first controller apparatus connected to the host apparatus and having a connection to the storage apparatus, the storage apparatus including a logical volume that stores data sent from the host apparatus and a virtual volume associated with the logical volume that is used for maintaining a copy of the data stored in the logical volume; and a virtual disk library apparatus including a tape library apparatus and a second controller apparatus connected to the virtualization apparatus, the second controller apparatus including an actual volume associated with the virtual volume used for storing the copy of the data maintained using the virtual volume, the tape library apparatus having a tape that stores the copy of the data stored in the actual volume, wherein the second controller apparatus has a path switching unit for conducting switching between a first plurality of paths that connect the second controller apparatus to the tape library apparatus and a second plurality of paths that connect the second controller apparatus to the first controller apparatus according to data transfer requests sent from the host apparatus, wherein the path switching unit sets the first plurality of paths to connect the second controller apparatus to the tape library apparatus in an initial state, wherein, upon the second controller apparatus receiving a first request sent from the host apparatus to transfer the copy of the data stored in the logical volume to the virtual volume using a specified path of the second plurality of paths, the path switching unit conducts switching to the specified path from a first path of the first plurality of paths that corresponds to the specified path to connect the second controller apparatus to the first controller apparatus, and the first controller apparatus transfers the copy of the data stored in the logical volume of the storage apparatus from the logical volume using the connection to the storage apparatus to the second controller apparatus for storage on the actual volume using the specified path, wherein, upon transfer of the copy of the data stored in the logical volume to the second controller apparatus, the path switching unit conducts switching from the specified path to the first path to connect the second controller apparatus to the tape library apparatus, and wherein, upon the second controller apparatus receiving a second request sent from the host apparatus to transfer the copy of the data stored in the actual volume to the tape, the path switching unit selects a free path from the first plurality of paths, and the second controller apparatus transfers the copy of the data stored on the actual volume to the tape library apparatus for storage on the tape using the free path.