ADSM-L

VM server 2.1.0.17 - performance when deleting tape volumes

1998-11-18 12:53:28
Subject: VM server 2.1.0.17 - performance when deleting tape volumes
From: Andreas Peikert <apeikert AT AMADEUS DOT NET>
Date: Wed, 18 Nov 1998 18:53:28 +0100
Hi all,

I have noticed that it took more than a minute to delete
a tape volume - until I deleted the volume history which
had grown up to > 38,000 records. After that action, the
volume history was just containing 1,300+ volumes.

Scenario:
Server:            ADSM/VM 2.1.0.17
Operating system:  VM/ESA 2.2.0 / RSU 9803+
Tapepools:         Reusedelay 4
                   Each pool is sized between 400 and
                   2000 voluumes
DB size:           ca 3.5 GB
Log size:          ca 800 MB

IBM could not give an answer to why this happened (PMR
was 97896) and I let this one go since the problem I had
was gone after this action. Also I just don't have the
time to look after such things at the moment and thought
to put it onto this list, perhaps someone can give an
explanation - and someone may also benefit from the info
given.

My assumption:
The Volume History files (at least oon VM) are not only
written to - there must be some internal action going on
that reads and perhaps even sorts the volume history when
a tape volume gets deleted. I don't know for what this
should be good, but I'll delete the volume hsitory from
today on daily to at max 5 days ago. This should not have
any side effects to disaster recovery as the DB backup
volumes are already deleted after 3 days and the rest can
be found in the (then restored) database (or am I missing
something here?).

Best regards

Andreas Peikert, Systems Programmer
   aMaDEUS Data Processing GmbH
   P.O. Box,   D-85424 Erding,   Germany
   Fon: +49 (0)8122 43-5805
   Fax: +49 (0)8122 43-3260
   email: apeikert AT amadeus DOT net