From owner-freebsd-questions  Fri Jul 27  8:22:38 2001
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Date: Fri, 27 Jul 2001 10:22:34 -0500 (CDT)
From: mark tinguely <tinguely@web.cs.ndsu.nodak.edu>
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To: freebsd-questions@FreeBSD.ORG, own3d@gmx.net
Subject: Re: Tape backup with software compression
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>  The problem is that i have a backup tape drive (Seagate STT38000N)
>  with a capacity of 4GB uncompressed and 8GB compressed. But it does
>  not seem to support hardware compression (at least i couldn't 
>  enable it with 'mt comp on').

have you checked the jumper settings for the tape drive? There usually
is a jumper that enables hardware compression.

second, are you streaming the drive -- delivering the data to the
drive fast enough so that the tape is not stopping and starting.

>  Now im looking for a way to do some software compression on the data
>  so that it fits one tape. That way it can be done by a nightly cron job.
>
>  As far as i have read in the archives and in the manpage, dump (which
>  seems be the best backup tool) does not offer any compression at all.
>  Right?

you can dump to standard output, pipe to gzip, and then dd to tape
to keep the fixed file records. Restore would be done in the opposite 
order.

hardware compress would be better than software compression, so I would
advise you pull out the drive and look at the jumpers located on the
back of the drive.

--mark tinguely.

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