A snapshot manager switches the roles of a production storage device and a
corresponding snapshot device by modifying read and write requests to the
devices. Thus, translation mapping information concerning the acting
snapshot device does not change, so a remote computing device can perform
a backup from the acting snapshot without having to restart every time
content is written to the production device. After the backup operation,
the snapshot manager can update the underlying data source from the
acting production device to capture writes to production that occurred
during the backup. The snapshot manager then reverts the roles of the
storage device and the snapshot to normal.