Patent ID: 8060777

Claim:
An information system, comprising: a host computer; a first storage apparatus connected to the host computer and including a first volume designated by a volume identifier; and a second storage apparatus connected to the host computer and including a second volume designated by the same said volume identifier as for the first volume; wherein, for backup purposes, the first volume and the second volume form a remote copy pair, and write data to the first volume is copied to the second volume; wherein, for I/O request purposes, the first volume and the second volume are recognized in the information system as a single volume labeled with the same said volume identifier, but accessible by alternative access paths designated with differing priorities; wherein, a priority of a first access path from the host computer to the first volume is higher than a priority of a second access path from the host computer to the second volume; wherein, when the host computer sends an I/O request designating the same said volume identifier, the I/O request is first sent to the first volume through the first access path; wherein, when the I/O request sent to the first volume through the first access path ends in an error, the I/O request is then sent to the second volume through the second access path; and wherein, upon receiving a write request sent from the host computer to the second volume through the second access path, the second storage apparatus suspends the remote copy, processes the write request and stores a write location of data recorded in the second volume based on the write request.