Hi Jeff,
We ran on unload-load on a 46GB database a few months back. The database was >90%
utilised before the unload-load and 52% afterwards. Besides the obvious benefit of
significantly reducing the database size, we have also seen better performance,
particularly with database backups.
That's the good news. The bad news is that all up our server was off the air for
around 24 hours. And that was with playing a few tricks. We normally run the database
with *SM mirroring enabled. We split the mirrors and used one set for the unload and
one set for the load. This also gave us an easy backout path without having to restore
the database. We then forced our 3590 tape drives to write in uncompressed mode with
resulted in multiple tapes being need to write the unload data. The advantage here is
that as soon as one tape was full, the unload would start writing to the 2nd tape and
we could use the first tape to start the load. So even though the unload took just
under 16 hours we were able to start the load after only 6 hours. The load took 17.5
hours. Note that the unload-load utilities do not support automatic tape libraries so
we also had to run the 3590s, which are in a 3494 library, in manual mode.
The unload-load ran on a 4-way RS/6000 R50 with 512MB memory, SSA disks, AIX 4.3.2 and
TSM 3.7.3.6.
regards,
Trevor
-----Original Message-----
From: Jeff Connor [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, 19 September 2000 2:04 AM
To: [EMAIL PROTECTED]
Subject: TSM 3.7 Database unload/reload
Our TSM V3.7 server running on OS/390 has a 32GB database
that's 85% utilized. We have been adding volumes over the last 5
or so years starting with ADSM version 1 and have never done an
unload/reload/re-org. I've been thinking of trying to unload and
reload this servers database and was wondering what other TSM 3.7
or 4.1 users have experienced after attempting an unload/reload.
I remember hearing stories in the past on the listserv about this
process running for days, database growing in size on the reload,
etc. I'm wondering if the long outage is worth it and what gains
you might have realized in terms of better performance, database
size reduction, etc. after unloading/reloading your database.
Any idea how many hours it might take to perform this process on
a 32GB database?
Thanks
Jeff Connor
Niagara Mohawk Power Corp
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