A virtualization apparatus presents a virtual volume to a computer that stores data to the virtual volume. The data is stored by the virtualization apparatus to a first logical volume at a first storage system. The first storage system includes data protection such that data stored to the first logical volume is copied to one or more second logical volumes, and the virtualization apparatus is able to switch paths to one or more of the second logical volumes during failover. When each write data is received from the computer by the virtualization apparatus, a sequence number corresponding to the write data is generated, and the write data and the corresponding sequence number are forwarded to the first storage system for storing to the first logical volume and the second logical volume. During failover, the sequence numbers are used to determine where to begin writing data to the second logical volume.