Software Preservation (was: SIMTEL...)

From: John Chris Wren <jcwren_at_jcwren.com>
Date: Fri Apr 5 13:26:52 2002

        No one seems to be addressing the issue that RAID is well and fine to guard
against hardware failure, but it will do *nothing* for file system
corruption. And even journalling systems like EXT2 and Reiser-FS don't
protect against a 'rm -rf *' as root accidently done.

        From my perspective, there are two types of backups, working and
historical. Historical backups should be cut to involatile media. Paper
tape (low density, low availability), and CDROM/DVD. CDROMs may delaminate
in 100 years, but they're not going to be erase near a magnetic field, are
*far* more reliable than any tapes I've ever used (not to mention portable,
in terms of filesystems, namely ISO-9660), and reasonable cheap. Downside,
of course, is only ~700MB per disc.

        CDROM drives will be around for a while. Sure, the same was said for
QIC-40 tapes, I'm sure, but we're *aware* that we have historical data on
CDROM, and as such, a CDROM drive sits on the shelf for future use. DVD
drives have much higher density, but cost more. At this point, I might
argue the point that media doesn't seem to be quite as portable as CDROM,
but I have far less experience with DVDs.

        Working backups are the current state of your system. They're not designed
to be recovered from in 20 years. They're the tapes you make every
night/week/month to gaurd against short term file deletes, hardware crashes,
and moving to newer/faster/higher density media (like that new 160GB Maxtor
we've all been coveting). I don't trust tapes. Never have. *Every* tape
system I've ever used in the last 20 years has, at some point or another,
generated a tape that can't be read. Be that bad tape design (QIC tapes),
poor tape quality, questionable drives, exposure to magnetic fields,
whatever, I've had tapes I can't read. And a tape I can't read might as
well be a tape I never wrote.

        One of my favorite and more cost effective ways to backup is to Ghost or
'dd' copy the drive to an identical device, then take that device out of
service. Once a week, I copy my 40GB Maxtor to another 40GB Maxtor. Not
perfect, since I usually don't take the 2nd drive off-premises, but since I
work where I live (or live where I work, depending on how you look at it),
it doesn't get a lot of chance to travel. That's my fault. 40GB of
infinitely reusable backup media (for medium sized values of infinite) for <
$100 isn't bad. That's the same as 5 DVD platters, and it won't wear out
anywhere near as quick.

        Everyone has a favorite backup scheme. At least, for those people that
actually *do* backups. These are just my opinions on a method that has
worked well for me.

        --John

> -----Original Message-----
> From: owner-classiccmp_at_classiccmp.org
> [mailto:owner-classiccmp_at_classiccmp.org]On Behalf Of Kent Borg
> Sent: Friday, April 05, 2002 13:38 PM
> To: classiccmp_at_classiccmp.org
> Subject: Re: Software Preservation (was: SIMTEL...)
>
>
> Someone wrote in an earlier message:
> > My idea is to build a Linux box with EIDE RAID setup to mirror a
> > couple BIG EIDE disks (80+ Gigabytes). Then have everything else
> > backup to those disks.
>
> I recently built a new Linux box with a pair of 60 GB disks (they were
> the sweet spot that week) in RAID 1, 256 MB RAM, CR-ROM burner, floppy,
> 850 MHz Duron, plus rudimentary sound, video, and ethernet on the
> motherboard.
>
> The whole thing, with a power supply, a case, and delivered (though in
> pieces) was under $600. (I already had a monitor, keyboard, mouse,
> and UPS.) Pretty nice system. I am typing this e-mail on it now,
> logged in from work.
>
> One ~little~ oopsie I just discovered today is that I accidentally
> made my /home partition RAID 0 instead of RAID 1...but I think I have
> figured out all the steps needed to change that.
>
> If I find myself wanting more space and 100+ GB drives come down in
> price, I might figure out how to squeeze 4 more disks into that same
> box as 300+ GB of RAID 5. (Keeping the RAID 1 because it is
> bootable.)
>
> -kb
Received on Fri Apr 05 2002 - 13:26:52 BST