From owner-freebsd-questions Fri Jul 2 10:44: 3 1999 Delivered-To: freebsd-questions@freebsd.org Received: from cc942873-a.ewndsr1.nj.home.com (cc942873-a.ewndsr1.nj.home.com [24.2.89.207]) by hub.freebsd.org (Postfix) with ESMTP id 8DCE114C10 for ; Fri, 2 Jul 1999 10:43:58 -0700 (PDT) (envelope-from cjc@cc942873-a.ewndsr1.nj.home.com) Received: (from cjc@localhost) by cc942873-a.ewndsr1.nj.home.com (8.9.3/8.8.8) id NAA23874; Fri, 2 Jul 1999 13:45:13 -0400 (EDT) (envelope-from cjc) From: "Crist J. Clark" Message-Id: <199907021745.NAA23874@cc942873-a.ewndsr1.nj.home.com> Subject: Re: Density for tapes with dump In-Reply-To: <199907021726.CAA61497@ares.maths.adelaide.edu.au> from Greg Lewis at "Jul 3, 99 02:56:57 am" To: glewis@ares.maths.adelaide.edu.au (Greg Lewis) Date: Fri, 2 Jul 1999 13:45:13 -0400 (EDT) Cc: freebsd-questions@FreeBSD.ORG Reply-To: cjclark@home.com X-Mailer: ELM [version 2.4ME+ PL40 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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): , 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 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message