ADSM-L

Re: Using FILE instead of DISK devclass to avoid disk under-utilization

2006-10-26 13:05:54
Subject: Re: Using FILE instead of DISK devclass to avoid disk under-utilization
From: Daniel Clark <dclark AT POBOX DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Thu, 26 Oct 2006 12:27:25 -0400
On 10/26/06, Thomas Denier <Thomas.Denier AT jeffersonhospital DOT org> wrote:
-----Daniel Clark  wrote: -----

>On 10/25/06, Thomas Denier wrote:
>> The first problem is that things get really ugly if the storage
>> pools collectively get larger than the shared disk space.
>
>Ugly in what kind of way? Clients don't just block until one of the
>FILE class devices on disk is migrated to a tape storage pool, and
>thus reset to scratch?

No, the clients keep trying to send data, and transaction failures
occur until some disk space is made available. In addition, when
a write to a file volume fails for lack of disk space, TSM will
allocate another scratch volume, get another write failure, allocate
another scratch volume, and so on until the storage pool involved
reaches its maximum number of scratch volumes. The empty scratch
volumes created this way end up with read-only access, and are not
deleted automatically by migration. I ended up writing a script to
find and delete empty, read-only, file volumes.

Ah, that sounds painful... so much for that idea :-(

Thanks so much for your response, which I am sure saved me at least a
day's work.

--
Daniel Joseph Barnhart Clark
http://www.pobox.com/users/dclark