From owner-freebsd-questions Mon Oct 11 12:45:29 1999 Delivered-To: freebsd-questions@freebsd.org Received: from palrel3.hp.com (palrel3.hp.com [156.153.255.226]) by hub.freebsd.org (Postfix) with ESMTP id 6BD7015682 for ; Mon, 11 Oct 1999 12:45:15 -0700 (PDT) (envelope-from darrylo@sr.hp.com) Received: from postal.sr.hp.com (root@postal.sr.hp.com [15.4.46.173]) by palrel3.hp.com (8.8.6 (PHNE_17135)/8.8.5tis) with ESMTP id MAA19310 for ; Mon, 11 Oct 1999 12:45:06 -0700 (PDT) Received: from mina.sr.hp.com (root@mina.sr.hp.com [15.4.42.247]) by postal.sr.hp.com with ESMTP (8.8.6 (PHNE_17190)/8.7.3 TIS 5.0) id MAA17841 for ; Mon, 11 Oct 1999 12:44:50 -0700 (PDT) Received: from localhost (darrylo@mina.sr.hp.com [15.4.42.247]) by mina.sr.hp.com with ESMTP (8.8.6 (PHNE_17135)/8.7.3 TIS 5.0) id MAA11982 for ; Mon, 11 Oct 1999 12:44:38 -0700 (PDT) Message-Id: <199910111944.MAA11982@mina.sr.hp.com> To: freebsd-questions@FreeBSD.ORG Subject: Re: Why use tape for backups? (was: backup method reccommendation?) Reply-To: Darryl Okahata In-reply-to: Your message of "Mon, 11 Oct 1999 09:47:48 EDT." Mime-Version: 1.0 (generated by tm-edit 7.108) Content-Type: text/plain; charset=US-ASCII Date: Mon, 11 Oct 1999 12:44:37 -0700 From: Darryl Okahata Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG FreeBSD Bob wrote: > What are the pros and cons of doing backups on CD's? * Small capacity. Even with compression, CD's don't hold much. Of course, if you don't have a lot to back up, this isn't an issue. However, if the data won't fit onto a single CD, plan on babysitting the computer and feeding it disks. * Speed is "decent", but not great (however, it can be great if you take price into account). Unless you have a recent-generation CDR/CDRW, the write speed is, at most, 4X, which is 600KB/sec. It's probably even worse with CDRW, as many drives seem to write CDRW media at a slower speed than CDR. Still, many inexpensive tape drives transfer data at well under 1MB/sec (early DAT drives, for example, transfer data at 150KB/sec), and so CD's aren't that bad. * Multi-disk backups are problematic. Unless you write your own backup software, I think you have to use split(1) to slice'n dice the output from dump/tar, and then write the resulting files to CDs. You basically need lots of free disk space, to use as a staging area. * If you're environmentally conscious, writing backups to CDRs (as opposed to CDRWs) is environmentally hostile. ;-) > I have been doing archiving on CD's for some months, and that seems > to be working, but, it is a real hassle to go through the motions of > tarring/compressing/isoing to write to a cd.... more than should be > necessary. Except for "feeding disks to the drive", it's straightforward to write scripts to automate this, as long as you have enough free disk space to use as a staging area. > Are there any good ways to use CD's as ``quasi tape devices'' rather > than mountable devices? Something like dumping to a file, then > dding the file directly to the CDdevice is what I would like to do. > Then if a recovery is needed, restore directly from the CD, like tape. What's wrong with mounting? It's easy to do. You can make a bootable FreeBSD floppy with the CDROM driver on it (I think the fixit floppy already has it). In that case, you can just store the backup as a file on the CDROM. When you need to restore, you boot from the floppy, mount the CDROM, and restore. No muss, no fuss. -- Darryl Okahata darrylo@sr.hp.com DISCLAIMER: this message is the author's personal opinion and does not constitute the support, opinion, or policy of Hewlett-Packard, or of the little green men that have been following him all day. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message