John, it depends. What platform(s) and more important, what network are you
using between platforms?

We are backing up 160 GB of SAP/Oracle nightly over an SP switch from one
node to another on an SP frame complex (RS/6000, AIX). This switch provides
100 MB (Byte, not bit!) per second capability. I also have a test system the
same size that we back up weekly over a FDDI link. Both go to a management
class that uses DLT drives as the primary storage pool. The nightly backup
runs just over three hours at about 59 GB/hr to three tape units
concurrently; the weekly process uses two tape units, runs for about 24
GB/hr.

I've tried the ADSM client compression but it slows down the backup in my
case (both of them). It DOES reduce network traffic significantly, but on a
moderately fast network this shouldn't be a problem. I am using the built-in
run-length compression in the current version of backint; this does not slow
the system down near as much, and it cuts down the amount of data written to
tape that needs to be copied later for off-site storage. In our case, that
160 GB becomes about 106 GB.

The other thing to watch out for is processor impact on your DB server
during the backup. With ADSM compression, you're going to get many
complaints about response time when the on-line backup runs or when the
off-line redo logs transfer. The backint compression is not quite as
cpu-intensive.

Tom Kauffman
Sr. Technical Advisor
NIBCO, Inc

kauffmant AT nibco DOT com
> ----------
> From:         John Rajca[SMTP:jrajca AT AGL.COM DOT AU]
> Sent:         Friday, May 15, 1998 11:08 AM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      ADSM Compression for large backups
>
> Hi,
>
> We are backing up NT and Novell servers without compression and are
> investigating using ADSM to backup over 100GB of SAP/Oracle/UNIX data
> every night.
>
> Can anyone tell me whether ADSM SAP/Oracle/UNIX client compression would
> speed up very large backups (and restores)?
>
> Thanks ..... John Rajca ..... Australian Gas Light Company
>