Provided is a method for mirroring data. A mirror policy indicating
volumes in a first storage system is processed to mirror to volumes in a
second storage system and volumes in the second storage system to mirror
to volumes in a third storage system. The third storage system is at a
first geographical location remote with respect to a second geographical
location including the first and second storage systems. A command is
transmitted to cause the copying of updates to the volumes in the first
storage system to corresponding volumes in the second storage system
indicated in the mirror policy. Upon an occurrence of an event, the
causing the suspension of the copying of updates to the volumes in the
first storage system indicated in the mirroring policy to the volumes in
the second storage system. During the suspension of the copying of
volumes between the first and second storage systems, causing the copying
of updates to the volumes in the second storage system indicated in the
mirroring policy to the volumes in the third storage system indicated in
the mirroring policy.