[Long] Auto-Recovery Boot CD

Alex Satrapa grail at goldweb.com.au
Mon Apr 22 18:23:58 EST 2002

Apologies if this has already been discussed to death...  I just felt it 
was time for me to make a fool of myself in public again.

Sam and I were doing our usual time-wasting at work, talking about the 
virtues of particular backup schemes, media and drives.  I mentioned 
that for the price of one (1) DDS4 tape drive, without any media, I 
could buy as many as 10 of the same hard drive that I was hoping to 
store copies of.

My backup needs are only:
  - Immediate protection against hard drive failure
  - Long term protection against loss of a machine

For the first bit, I can probably get by with disk mirroring.

For the second bit, I would be looking at tape or CD storage.  I 
suggested that I could get by simply archiving all my user-created data 
(stuff in /home/alex) as well as everything in /etc/ (since I have 
customised some stuff like Samba).  That would leave enough space on my 
backup media (650 or 700Mb CD-R) to have:
  - a bootable Debian installer (~ 184Mb [1], or ~ 30.7Mb [2]),
  - the output of "dpkg --get-selections", and
  - other bits like debconf.conf, if they aren't
    already in /etc/

Thus every backup I make could be used to boot a machine, install a base 
Debian package, use "dpkg --set-selections" and various apt-get trickery 
to install all the Debian packages that were previously installed, then 
finally recover my data.

This "recovery CD" would be entirely dependent on having some place to 
download all its packages from - it's a machine-rebuilding CD, not a 
Debian distribution CD.

Can anyone spot obvious flaws in this idea?

One obvious problem I can see is that I may just want to get the data, 
rather than install Debian GNU/Linux over my friend's Slackware 
machine ;)  In that case, I'd just mount the CD after the machine has 
booted off its usual boot media.

Another is that I'd have to make sure that all home-grown packages are 
backed up too.  The installer would have to know about those.  I don't 
think I'd include a kernel image, since the chances are I wouldn't find 
another motherboard and processor quite like mine in a hurry.

Does anyone know how hard it would be to add in a post-installation 
script to the stuff on the default Debian network installer CD, that 
would do the package selection and data recovery after installing a 
minimal Debian base?

One day I'll get that CD-R drive I keep promising myself, then I can 
start putting my ideas into practice[3].  I might even think about 
running nethack on the main VC while the system is being 
installed/recovered 8)

If this has already been done before, I'd love to read about it - can 
you point me at a web page?


[1] Debian On CD - http://www.debian.org/CD/netinst/
[2] Debian 3.0 Netinst Images - http://people.debian.org/~ieure/netinst/
[3] Creating an El Torito bootable CD - http://mlp.rhic.bnl.gov/RescueCD

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