ADSM-L

Re: Archive to a single tape?

2000-02-22 17:00:37
Subject: Re: Archive to a single tape?
From: Russell Street <russells AT AUCKLAND.AC DOT NZ>
Date: Wed, 23 Feb 2000 11:00:37 +1300
> Our backup administrator keeps offsite archives in house until the 4 tapes
> are full.  It was explained to me that ADSM put files on each of the four
> tapes instead of filling up one at a time.

Have you set up your Archive Copy Group so that it goes directly to
tape?  If so, then you will get as many tapes filling as there are
concurrent streams running.  Only one client can write to a tape at
one time.

> I can understand this from a performance point of view.  But if I'm only
> archiving 1 or 2 tapes of data can we force ADSM to do 1 tape at a time?

> Thanks, it's realy scary having archives hang around for up to 2 months
> before going off site?


There are (at least) three work arounds:

1.  Use a copypool to make a copy of the data in the archive tape
pool.  When you want to send the data off site, simply update the
copypool tape's status to 'offsite'.  ADSM will stop writing on the
tape and use another from the scratch list.

2.  You could simply mark your archive tapes "readonly" and send them
off site when necessary.  The downside is you will end up with a lot
of half-empty tapes off site.

3.  Establish a DISK based primary pool and have the clients archvie
their files to that pool.  Set the next storagepool for the DISK pool
to the tape pool and the number of migration processes to 1.

Files will flow from the client to the DISK pool, then be moved in
single file onto the tape pool.

The disk pool will need to be large enough so that the tape drive can
empty it faster than the clients are putting data onto it.


Russell
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