I'd say you are correct if you are only concerned about actual bytes in the
tape pool.  I do client compression because I have a very slow network.  On
some of my clients ADSM compresses 90%+   That means I can do the client
backup with maybe 10% of the impact on the network, of course I am adding
cpu overhead to the client.   However, most of my clients have excess cpu,
especially at 1-2AM when the backups run.

> ----------
> From:         Kelly J. Lipp[SMTP:lipp AT STORSOL DOT COM]
> Sent:         Tuesday, January 12, 1999 8:10 PM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Re: 3570 Magstar device and compression
>
> I'll ask a slightly different question but related.  Netware offers
> compression, correct?  When the client backs up files in a compressed
> netware file system, is the data uncompressed before it is sent?  I would
> think it is, but if so, decompressing, and then compressing again with
> ADSM would seem to me a bit slow.
>
> I haven't seen any situations where compression=on has worked well.  I'm
> an old hardware guy and I've got to think that the hardware compression
> will always be better than software compression.
>
> Kelly Lipp
> SSSI
>
> -----Original Message-----
> From:   Tom Haddad [SMTP:thaddad AT COLUMBIAENERGYGROUP DOT COM]
> Sent:   Tuesday, January 12, 1999 1:47 PM
> To:     ADSM-L AT VM.MARIST DOT EDU
> Subject:        3570 Magstar device and compression
>
> I have 3570 devices (models B and C) running ADSM v3.1.
> They have been operational for a short time, but I have questions about
> client
> compression.
> The drives are defined as FORMAT=DRIVE and DEVTYPE=3570.
>
> In regards to Netware (4.11) clients, how can I maximize my compression
> gain??
> I attempted to leave COMP=NO at the server (for the node) and COMP OFF in
> the
> OPT file and let the hardware take
> over with compression. Looks Iike I average about 7 or 9G max on a tape
> cartridge as they became full.
> Next I want to put COMP ON in the OPT file and see if I get more
> compression..
> Any help?
>
> I think my NT clients gain an overall better compression rate than my
> Netware
> clients..hmmm!!
>
> Looks like compression gain is driven by  the type of client(data),
> hardware...etc..
>