Date: Fri, 2 Jul 1999 13:45:13 -0400 (EDT) From: "Crist J. Clark" <cjc@cc942873-a.ewndsr1.nj.home.com> To: glewis@ares.maths.adelaide.edu.au (Greg Lewis) Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Density for tapes with dump Message-ID: <199907021745.NAA23874@cc942873-a.ewndsr1.nj.home.com> In-Reply-To: <199907021726.CAA61497@ares.maths.adelaide.edu.au> from Greg Lewis at "Jul 3, 99 02:56:57 am"
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Greg Lewis wrote,
> Hi all,
>
> My home system is currently a 3.0-R beast which I'm wanting to upgrade to
> 3.2-R. Shouldn't be a problem, but I'd like to do a backup first. I have
> an atapi tape drive which detects as
>
> wdc1: unit 0 (atapi): <Seagate STT8000A/5.02>, removable, accel, dma, iordis
> wst0: Drive empty, readonly, reverse, qfa, ecc, 512b
> wst0: Max speed=600Kb/s, Transfer limit=52 blocks, Buffer size=728 blocks
>
> (a Seagate TapeStor Travan TR-4 tape drive). Unfortunately the density
> seems incorrectly set as when I try to dump my file systems it clearly
> gets its calculations wrong:
>
> DUMP: estimated 3821513 tape blocks on 97.88 tape(s).
On the dump(8) manpage,
-a ``auto-size''. Bypass all tape length considerations, and enforce
writing until an end-of-media indication is returned. This fits
best for most modern tape drives. Use of this option is particu-
larly recommended when appending to an existing tape, or using a
tape drive with hardware compression (where you can never be sure
about the compression ratio).
Just adding the '-a' option should fix your problem. That's what I use
for my Exabytes.
--
Crist J. Clark cjclark@home.com
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