ADSM-L

Re: Problems with migration from disk to tape storage pool

1999-08-23 10:59:57
Subject: Re: Problems with migration from disk to tape storage pool
From: "Bernd Finger - Sun SAP Walldorf SAP Eng. Technical Solution Center" <Bernd.Finger AT GERMANY.SUN DOT COM>
Date: Mon, 23 Aug 1999 16:59:57 +0200
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> From: John Schneider <jdschn AT ibm DOT net>
> Subject: Problems with migration from disk to tape storage pool
> To: ADSM-L AT VM.MARIST DOT EDU
>
> Greetings,
.
.
.
>     So we set up a disk file pool of 3GB in size, and changed
> the backup copygroups to point to it.  The disk file pool is
> set up to migrate data with a high and low point of 0%, and
> to migrate to the tape storage pool.  My understanding was that
> when the clients started their backups they would write their data
> simultaneously to the disk storage pool, and immediately a
> migration would start which would grab a tape drive and
> copy data out of the disk storage pool onto the tape.  Effectively
> a bunch of slow clients would now be writing their data through
> a disk pool to a single tape drive.  The throughput of one client
> would not go up, but only one tape drive would be in use, instead
> of four or five being used for hours.
>     But it is not working as expected.
.
.
.
Always set hi high enough to ensure all nodes can complete their backup to 
disk. I
always had problems when the migration started during backup (this was under 
AIX, but
I'm sure the behaviour is the same under other OSs).

I used to schedule a job to set hi to 0 to force migration after all client 
data was
backuped to disk (e.g. at 05:00), and another job to set hi to 90 or after 
migration
was completed (e.g. at 15:00).

Other experiences ?

Bernd