[Coats, Jack]  [snip]
> Question:
>
> Are all the backups being serviced and written to the disk pool in some
> round-robin fashion?
>
> or, is any 1 client backup session being totally completed before another
> client session is started?
>
> or, just how does multiple concurrent client sessions operate in this
> scenario?
        [Coats, Jack]  [snip]

        The basic answer is yes, since all the clients send their data, and
the data is being written to the disk pool as they arrive. Does it tell one
client to wait as another transmits?  No.
        All sessions are being serviced simultaneously / concurrently.  Once
the file is on disk, the database has an update issued to save the
information.  Once the disk pool fills enough, typically we roll (migrate)
to tape, well before the disk fills.

        If you do compression or encryption that is done on the client side,
not on the server.  So that could be a CPU intensive process on the client,
but adds no additional load to the TSM server, and the compression results
in smaller files on the server disk.  But tape drive compression is
basically eliminated even if it is enabled.

        The speed of the backups are usually limited by the network speed,
not speed of the disk, tape, or CPU.  Restores are limited by network and
tape speed, and the fact that, after a while, every client will have
basically normal distribution of their files over all the onsite tapepool
tapes (assuming you use only one tape pool).  So you could have to spin lots
of tapes to restore a client.

        I hope this helps a little.