A method and apparatus for data backup is disclosed in which prior to
actually performing a backup operation from a subscriber computer, the
backup server device checks a specified server to determine if parts of
the subscriber data to be backed up can be backed up or replicated from
data on the specified server. If it can, the backup server uses that
specified server to create a backup of the subscriber data to be backed
up. If it cannot, then the data is backed up from the subscriber
computer.