On Wed, 23 Feb 2005 asr AT ufl DOT edu wrote:
> In order to reclaim a given volume, you really need three different ones: The
> target volume, and the volumes "adjacent" to the target: The one with the
> other half of the aggregate which comes first on the target volume, and the
> one with the other half of the aggregate that comes last.
>
> I don't think I've been able to find a way to find which volumes these are
> without actually running the expiration or move data and failing the mount.
> Is there a good way to find this information out?
If I understand your scenario correctly, then I think I've run into this.
My not-so-elegant solution was to start an 'audit volume' on the tape that
I intend to run a 'move data' against. If it's the only tape needed, then
the audit will start up okay and can be cancelled; if there's at least one
other tape needed, audit will complain that a required volume is offsite,
specify the needed volume, then terminate. Unfortunately, audit only
specifies *one* required offsite volume, so you have to do another audit
after the needed volume is marked onsite in order to see if a 2nd offsite
volume is needed.
I thought about trying to script this to the point where you could at
least know all of the volumes needed before ever inserting any tapes; that
way you could make only one 'offsite trip'. I think that would involve
marking a volume onsite before inserting it, attempting the audit,
capturing the needed volume name if the audit fails, cancelling the audit
if it doesn't (and maybe dealing with a failed mount?), etc. I never
actually spent any time coding/testing this, though.
This is admittedly very ugly; I tried getting IBM to give me some SQL that
could *quickly* determine the needed volumes, but was told it's not
possible. I'm not sure why...presumably it has to do with the "it's not
really a relational db, and the SQL interface is only a convenience good
for some things" business; all I know is that audit knows *immediately*
which other volume is needed.
Fortunately for me at least, I no longer have a need to do this sort of
thing.
Regards,
Bill
Bill Kelly
Auburn University
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