It is going to tape.  I would rather it go to disk but some of the files
are huge and my disk pool is usually nearly full when it starts.  I know
it is being slowed down by conflicting with disk to tape migration, to
some extent.  The network interface is GB Ethernet and has a lot more
capacity availably at that time.
        If I am successful at backing up separate groups, will I be able
to restore it just as fast?   Ot is this something that I would be able
to do if I work out what tapes are written to and what filespaces are on
them.
Matt