From owner-freebsd-questions Sun Oct 10 19:21:28 1999 Delivered-To: freebsd-questions@freebsd.org Received: from phoenix.volant.org (phoenix.volant.org [205.179.79.193]) by hub.freebsd.org (Postfix) with ESMTP id 21460151F5 for ; Sun, 10 Oct 1999 19:21:21 -0700 (PDT) (envelope-from patl@phoenix.volant.org) Received: from asimov.phoenix.volant.org ([205.179.79.65]) by phoenix.volant.org with smtp (Exim 1.92 #8) id 11aV5Q-0004tB-00; Sun, 10 Oct 1999 19:21:16 -0700 Received: from localhost by asimov.phoenix.volant.org (SMI-8.6/SMI-SVR4) id TAA26943; Sun, 10 Oct 1999 19:21:12 -0700 Date: Sun, 10 Oct 1999 19:21:12 -0700 (PDT) From: patl@phoenix.volant.org Reply-To: patl@phoenix.volant.org Subject: Re: Why use tape for backups? (was: backup method reccommendation?) To: Greg Lehey Cc: freebsd-questions@FreeBSD.ORG In-Reply-To: <19991011112417.S78191@freebie.lemis.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 10-Oct-99 at 18:54, Greg Lehey (grog@lemis.com) wrote: > > A second disk gets you only one generation of backup. And if > > something catastrophic happens during the backup, it may be > > corrupted too leaving you with -no- backup. > > Well, that can happen with tapes, too. Yes, if you are foolish enough to reuse a single backup tape instead of at least switching back and forth between two. (Or, better yet, having a real backup cycle among multiple tapes.) > > If you want multiple generations; and/or have many disks or systems > > to backup, you can't beat the price per bit or reliability of tape. > > This used to be the correct answer. I'm no longer sure it is. > Certainly I think that the current generation of tape units is *much* > less reliable than hard disk. The media are cheaper, but when I > consider the number of DDS drives I wore out doing regular daily > backups, I think that backing up to disk might have been cheaper. Maybe DDS wasn't the right choice. I've been using Exabyte 8mm backups for years, both personally and at various companies; and I've had more problems with disk drives going bad than I have with tape drives. Also, the physical density is much higher for tapes. I can keep archival tape backups in a -much- smaller space than the equivalent disk volume. For personal use with a single desktop machine, something like a Jaz drive might be a reasonable alternative to tape; especially since it would also be useful as a non-backup removable media drive. But it really doesn't scale well. For example, it is very difficult to do a scheduled backup that won't fit on a single cartridge. But with tapes, per-tape capacities are much higher (40Gb or more) and auto-loaders are readily available. I'd love to find a viable alternative to tape; but so far, nothing has been able to quite measure up on the combination of price-per-bit, archival quality, overall capacity, and ease of use. Maybe in a couple of years (re)writable DVD-ROMs with a carrousel be an option; but for now, tape rules. -Pat To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message