ADSM-L

Re: Mirrored DELETE DBVOL, LOGVOL?

2002-05-24 09:47:56
Subject: Re: Mirrored DELETE DBVOL, LOGVOL?
From: Zlatko Krastev <acit AT ATTGLOBAL DOT NET>
Date: Fri, 24 May 2002 16:44:41 +0300
You are as much as possible close to target. The only issue you have to
count is AIX mirroring does not provide the database write consistency TSM
mirroring provides.
Regarding AIX LVM - it is not so "friendly" because is more complex and
flexible.

Zlatko Krastev
IT Consultant




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Subject:        Re: Mirrored DELETE DBVOL, LOGVOL?

I think I have found a way, although it's a little cumbersome.

First, have AIX mirror one of your TSM mirror volumes. Now DELETE DBVOL
the other member of the pair, and you're still mirrored - by AIX - while
you DELETE DBVOL the primary half.

The AIX Logical Volume Manager is nowhere near as friendly to use as
TSM's own database mirroring facility, but it does work.

Roger Deschner      University of Illinois at Chicago     rogerd AT uic DOT edu


On Fri, 10 May 2002, Reinhard Mersch wrote:

>Roger,
>
>I agree, I also feel very uncomfortable living without a mirror, even
>for a limited time. The admin interface should be enhanced to allow for
>distinguishing between removing a DBCOPY from deleting the entire DBVOL
>including all mirrors (and hence moving the contents while all mirrors
>are in place).
>
>In the past, I have always added the new volume as a mirror first,
>then deleted an old copy, then added a new mirror, ...
>Since this procedure does not allow changing the volume size, the volumes
>on my nearly 8 years old server are now much too small. The necessary
>consolidation exposes me to the danger described by you, so I'm
>hesitating ...
>
>Roger Deschner <rogerd AT UIC DOT EDU> schrieb:
>> Oh, I guess it's just my paranoid mind at work again, but DELETE DBVOL
>> scares me. I'm using it to migrate the TSM Database from old disks to
>> new, faster disks.
>
>> So, I attached the new dbvol and its mirror, fiddled with EXTEND DB and
>> REDUCE DB to make it right, and did DELETE DBVOL on the old mirror.
Then
>> I did DELETE DBVOL on the old primary copy.
>
>> Oops! Now I'm really exposed! There is only one copy of the old
database
>> volume, while this rather lengthly copying process proceeds.
>
>> Is there any way to do a DELETE DBVOL in a mirrored way - that is
delete
>> all mirrored copies of a DBVOL at once, so that if a disk crashes in
the
>> middle of it, I will not lose my Database? That's the whole point of
>> Database mirroring, isn't it?
>
>> I'm starting to think AIX JFS mirroring might have some advantages over
>> TSM Database/Log mirroring.
>
>> Roger Deschner      University of Illinois at Chicago rogerd AT uic DOT edu
>
>--
>Reinhard Mersch                        Westfaelische
Wilhelms-Universitaet
>Zentrum fuer Informationsverarbeitung - ehemals
Universitaetsrechenzentrum
>Roentgenstrasse 9-13, D-48149 Muenster, Germany      Tel:
+49(251)83-31583
>E-Mail: mersch AT uni-muenster DOT de                       Fax:
+49(251)83-31653
>
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