In a configuration in which it is necessary to transfer data from a first
storage system to a third storage system through a storage system between
the storage systems, there is a problem that it is inevitable to give an
excess logical volume to a second storage system between the storage
systems. A remote copy system includes first storage system that sends
and receives data to and from an information processing apparatus, a
second storage system, and a third storage system. The second storage
system virtually has a second storage area in which the data should be
written and has a third storage area in which the data written in the
second storage area and update information concerning the data are
written. Data sent from the first storage system is not written in the
second storage area but is written in the third storage area as data and
update information. The data and the update information written in the
third storage area are read out from the third storage system.