An exemplary storage system according to the invention includes a first physical storage apparatus providing a first real volume and a second physical storage apparatus providing a second real volume to form a copy pair with the first real volume. The first physical storage apparatus provides a first host with a first storage identifier and a first volume identifier for the first host to access the first real volume. The second physical storage apparatus provides a second host with at least a part of a first virtual storage apparatus including a first virtual volume allocated the second real volume. The second physical storage apparatus assigns the first volume identifier to the first virtual volume and the first storage identifier to the first virtual storage apparatus.