Re: Scratch tapes...

If you really have lots of disk to work with, you would configure disk pools
to hold one night's worth of backup load (check dsmaccnt.log for actuals,
size the disk pool at 125% or more), then trigger migration when backups are
finished.  Then, only send the big globs straight to tape;  send all the
little backups to diskpool, so you get to the morning with the tape
librarian can manage tape pool.

The main thing you need is to size the silo to match the backups... using
the "Getting Started" book, starting point is to do some math on your
retention versus silo capacity... and never count more than "native" tape
capacity.  You'll need about half the silo to handle copy pools &
db-backups, especially if you're trying to run unattended;  except for
checking out offsite media, the silo should hold all the backup data - if
not, you'll need a full-time tape librarian to shuffle tapes in & out.

Regards,
Don



 -----Original Message-----
From:   Ray [mailto:ray AT OPS.SELU DOT EDU]
Sent:   Monday, January 22, 2001 11:09 AM
To:     ADSM-L AT VM.MARIST DOT EDU
Subject:        Scratch tapes...

Hello all,

I'm relatively new to TSM, and inherited a 3.7 server on AIX with one
3570 library (19 tapes).  We do oracle backups and Solaris/Linux/Aix/NT
backups to the same storage pool.

The problem is we're backing up up a lot of data.  Occasionally TSM will
use up all the tapes, leaving no scratch volumes.  I have expiration set
to run every 6 hours, but with no scratch volumes, space reclamation
fails, and TSM is sort of stuck.  At this point i have to manually move
data from one volume to a disk storage pool, to get an empty volume (or
scratch tape) so TSM can get enough "breathing room". Then reclamation can
free some volumes.  But in the meantime all the previous night's backups
failed.

What is the best rememdy for this?  Should i lower the reclamation
threshold? It is at 60 now...  Also i have plenty of disk space to play
with.  Should i define a reclamation storage pool??  The redbook says a
reclamation storage pool is good for when the library only has one drive,
but it seems it might help in my situation.  Thanks for any advice..

-Ray
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Ray DeJean                                       http://www.r-a-y.org
Systems Administrator               Southeastern Louisiana University
IBM Certified Specialist              AIX Administration, AIX Support
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