It's reasonable to set mount retention to 5 minutes or so.
As to why reclamation is reluctant to release a tape until it finishes
with it, I don't know why, I just know it's so, at least on some
libraries.  i don't hink it has anything to do with mount retention - I
think it's more like TSM wants to finish a complete tape before it sets
aside its reclamation process for the higher-priority restore.

But I'm just speculating as to why.  Maybe somebody else can enlighten
us.


Gerald Wichmann wrote:
>
> * What happens if someone kicks off a restore that requires a tape and both
> > tapes are being used (if they=92re both being used) as in the above insta=
> > nces?
> > I=92m assuming the higher priority process (restore) halts the
> > migration/reclamation like it does on a single drive library and grabs a
> > drive=85?
> Yes but - if a tape is being reclaimed, you may see a forty-minute wait
> before TSM gives up the drive!  Better to leave one drive free for
> restores.
>
> Is this due to the default 60 minute mount retention? I.e. reclamation as a
> process stops, but the tape it was reclaiming remains mounted in the drive
> until TSM unmounts it.
> Which brings to mind the question of mount retention.. I know 60 is default
> but I've ran into numerous situations where something didn't run or hangs
> for a long time because my tape library had a tape mounted in it's drive
> essentially doing nothing (IDLE). What are the cons to lowering mount
> retention to something more reasonable like 5 minutes? Or for that matter
> why not 1 minute? If it's not doing anything may as well unmount it I say!
> Thanks,
> Gerald

--
Mr. Lindsay Morris
Mr. Lindsay Morris
Gresham Enterprise Storage
lmorris AT openmic DOT com
606-253-8000