ADSM-L

Re: DIRMC - disadvantages only?

2000-11-28 10:14:07
Subject: Re: DIRMC - disadvantages only?
From: William Boyer <wboyer AT PTD DOT NET>
Date: Tue, 28 Nov 2000 10:13:43 -0500
Another disadvantage is reclamation of the copypool for the DIRMC disk pool.
If the primary pool is a disk pool, then TSM server only reads 1
file/directory at a time during reclamation of the offsite copypool for the
DIRMC primary pool. This makes the reclamation process REAL slow! Tivoli
says 'working as designed' and would only take an enhancement request on it,
not an APAR. Originally my storage pool was:

DIRPOOL primary DISK
DIRCOPYPOOL     copypool TAPE

To get around this 'feature' a co-worker of mine came up with this new
stgpool structure:

DIRPOOL primary DISK: NEXTPOOL->DIRFILE
DIRFILE primary SEQUENTIAL on DISK
DIRCOPYPOOL     copypool TAPE

The DIRPOOL is small, only 50MB. The DIRFILE is set to 100MB filesize. The
client backkups put the directories in the DIRPOOL and then the daily server
processes are:

BA STG DIRPOOL DIRCOPYPOOL
BA STG DIRFILE DIRCOPYPOOL
UPD STG DIRPOOL HI=0 LO=0       (Migrate for DIRFILE)

This way when reclamation occurs on DIRCOPYPOOL, the primary pool is a
SEQUENTIAL pool and then TSM reads them in batches. It's a LOT faster this
way.

One problem I encountered with DIRMC was with some of the older TSM and ADSM
clients. I was getting errors on the client when trying to send a directory
entry that the  server was out of storage pool space in the DIRPOOL. Turns
out this is an APAR (Can't remember the number) in the client where it
calculates the size incorrectly on NT clients with security assigned for
directories. To fix this upgrade to the latest client, or add
SKIPNTPERMISSIONS YES to the DSM.OPT file on the client.

Bill Boyer
DSS, Inc.

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