Date: Sun, 10 Oct 1999 19:21:12 -0700 (PDT) From: patl@phoenix.volant.org To: Greg Lehey <grog@lemis.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Why use tape for backups? (was: backup method reccommendation?) Message-ID: <ML-3.4.939608472.9084.patl@asimov> In-Reply-To: <19991011112417.S78191@freebie.lemis.com>
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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
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