Re: backing up a complete Debian GNU/Linux system
George Bonser <grep@shorelink.com> writes:
> On Tue, 3 Aug 1999, xxxxx xxxxx wrote:
>
> > Hi!
> > Could anyone tell me what's a good hardware/software
> > combination to use to make frequent FULL backups
> > of a Debian system
> > (operating system, "applications", and data).
> > I asked recently at a fairly large Linux group meeting,
> > and everyone seemed suprised by the question and there
> > were no good answers, which completely floored me...
> > how could anyone smart enough to use Linux not back
> > up their entire system RELIGIOUSLY?
>
> You do not backup the application binaries because you already have a
> backup ... either the CDROM you installed from OR the debian archive. I
> would never trust a backup of my binaries ... what if one of them has been
> replaced with a trojaned version?
I guess I don't see the logic here. If one of the binaries on your
backup has a Trojan that, presumably, means that before you did the
backup you were running a system that had a Trojan. I would assume at
that point the damage has already been done. Besides, assuming someone
slipped a Trojan onto your system in the first place, restoring all
your config files as they existed prior to the backup would allow them
to just log in and introduce it again.
The only chance I see of defeating a Trojan is detecting it and
defeating the method used to introduce it in the first place. Also,
the fact that such Trojans are so rare on Unix and Unix-like systems
would make it a minor concern for me.
Anyway, it's standard practice in large installations to back up
practically everything for a level 0 backup, excluding things like
/tmp, /dev (sometimes) and /proc.
The only reason I wouldn't back up binaries was if I had a limited
medium, in terms of space or time, for the backups.
> If things are so bad that you must
> completely restore, you are probably better off reinstalling.
I suppose this might be true in some cases. I'd certainly prefer
restoring a backup to a complete reinstall.
> There are several good backup methods ... taper, amanda, etc. and several
> commercial backup utils for Lnux too.
Anyone else tried afbackup? I think it's great. Just about everything
I've ever looked for in a backup utility. It's a bit of a steep
learning curve but once you have it configured and running it requires
minimal hand holding. Just slap the incremental command in a cron
entry and you're off.
> As for backup devices, if you are talking about more than a few gig, best
> to go to DLT tape. A CDROM only holds a bit more than half a gig. You are
> going to spend all night swapping CDROMs.
Has the price equalized on DLT drives and tapes? The old wisdom said
that it's better to get a DAT or 8mm drive if you were going to need a
relatively large set of tapes because the DLT tapes were (are?) so
expensive. Anyway, it's easy to figure out just:
Tape Drive price + Number of tapes * Price of single tape = total
and see which total comes out lower. I don't think you'd be sorry
choosing either DLT or DAT/8mm, barring price concerns, assuming you
already have SCSI.
Anyway, my trusty 4 year old, refurbished, 4mm DAT drive has been
going strong for a long time and it's served me perfectly as a backup
device. Of course being that old it's slow as dirt, but I'm usually
not in a rush for backups.
Gary
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