[rescue] Backups

Jeffrey Nonken jjn_rescue at nonken.net
Thu Jun 16 09:42:26 CDT 2005

Lots of good stuff on DVD writing clipped. Not all was relevant, I
should have been more specific. My bad.

My current setup uses Dantz Retrospect and one (or more) DDS-3 drives.
It is an automated solution that I have running daily full/incremental
backups for one week, cycles every week, cycles one tape set every 5
weeks, keep indefinitely. (I've been re-using older sets to avoid
spending lots of cash on new tapes, but we're still talking a couple
years' worth of backups.

The automation is such that most times I just need to swap tapes. It
runs about 5 hours/day.

The version and license of Retrospect that I'm running will back up
MacIntosh clients (of which I have none ATM) and Windows clients and
will, if installed on a Windows server, back up that server (but won't
back up remote servers). It will burn to CD but not DVD.

I do have access to a copy of a later version that will write to DVD.
When I tested it on my El Cheapo Brand (OK, IO Magic branded BTC) DVD
writer it was able to write the first DVD, but when it tried to span
it failed, and the writer never recovered until I did a power-cycle.
I'm not sure if that's the software fumbling something or the writer
handing something badly. It's possible that the newest version of
Retrospect will handle it fine. It's possible that a Plextor won't
have this problem. A Retrospect upgrade will cost on the order of $600
and I'm not willing to spend that; a new drive might be in the works
but I'm on a budget, so reluctant to shell out the money just yet. I
do have a working backup system, so I can afford that choice.

One of the characteristics of what I'm doing is backing up multiple
clients across my network. I'm planning to migrate much of my stuff
over to Unix. Unfortunately Retrospect won't do Unix backups without a
license upgrade, which really means updating at this point. Especially
if I want to write to DVD.

So what I'm thinking of doing is replacing Retrospect with something
free (as in beer) that will allow me to backup mixed clients over a
network. Looking at media prices and drive prices I concluded that I
could do worse that DVD. It's a popular format, so I'd have the
advantage of economies of scale that tapes won't give me.

It could be I might find some of those 35 cent deals on the DLT drives
you guys were talking about  :^) but I'd not seen any for the format I
was familar with. I also feel twitchy about trusting really cheap tape
drives. Why are they so cheap? How much wear is on those heads? Ditto
cheap used media. One of the advantages of DVD is that I can get new
drives and media cheaply. I'll have to swap media more often, but hey,
this is a home backup. It's not that critical. Performance will be
Good Enough.

So the real question is: Can I do the backups reliably using DVD
media? Don't talk Ghost and Nero. I use Nero all the time to archive
data, but I'm talking about automated backups. Ghost... is good at
what it does but for me it's not a valid backup solution.

If reliable DVD backups simply aren't possible with current
technology, then I'll continue to pursue tape solutions. Meantime, I'd
like to consider how to use DVD media. And I was wondering if anybody
had any experience using it in some other situation than manual
archiving using Nero et. al. Specifically I need to know if the
spanning problem is inherent or if it's a limitation of my hardware
and/or software. I once tried using CD-RW media for backups which
worked fine on the first write (when I used expensive Ricoh media) but
not on rewrites. Is this an ongoing problem? Dunno.

Streaming the data shouldn't be an issue because I believe the backup
software uses packet writing (same idea as what DirectCD does) which
allows them to append to discs without having to do multiple sessions.
Modern drives also include Justlink/Burnprooff/whatever, plus at least
one software solution I'm considering includes the ability to buffer
the data to hard drive before writing to media.

And by the way, those Windows folks with coaster problems: Check the
driver settings to make sure that both your hard drive(s) AND your DVD
writer(s) are running in DMA mode. It's been my experience that
Windows doesn't always use that mode on optical drives by default.
(Check the IDE channel advanced settings, not the drive settings.)
Another good thing is to make sure your drive is primary on its own
bus. Obviously you can ignore that if you're using a SCSI drive. :) I
don't know if that last bit applies to all operating systems or just
Windows. It might be an inherent issue with IDE, rather than an
OS-specific issue.

Maybe one of you more erudite folk has the answer to that.

Note: You know, I thought I had the latest firmware on this drive, I
updated it a couple months ago. Let me burn to some cheap media it
wouldn't properly recognize before. But today I ran the updater and it
said I had 0151 but 0251 was available. Maybe that will solve my
spanning issue? Don't know. Have to read the release notes, and
anyway, right now I'm more doing research than experimenting.

Anyway, thanks for your time.

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