Re: [Duplicity-talk] Restore question

[Tim Riemenschneider]

Dylan Martin schrieb:
> It sounds like "never back up something that comes on an install disk"
> might be a best practice.
>
> My problem with that is, I have a hard time keeping track of what is
> unchanged from the install disk and what isn't.  I used to only back
> up user data and not system data, but then I had a real crash, and
> suddenly all those little changes, installed packages and whatnot come
> to the fore.  If I was organised enough, I could make some sort of a
> snapshot of the initial install state and then backup only the delta.
> Of course, that relies on knowing exactly which packages I installed
> at the beginning.
> So, you see what I'm getting at here, there's a lot of opportunities
> to screw up.
>
> As a sysadmin with scars, I can say that a backup system is only as
> good as it's restore system.  When I say system here, I don't mean
> duplicity, I mean the entire process (boot media, duplicity, attaching
> to restore media etc.. etc...)  A restore system should be simple and
> quick and foolproof.  When you're restoring data, you're usually
> stressed out, tired, possibly drunk, maybe even talking someone else
> through the process over a telephone and the other person is the night
> janitor who's never used a computer before and you don't have a first
> language in common.
>
> Er... I think that was kindof a tangent, but an important one in it's way.
>
> So, I'd be very interested in learning about other people's restore practices.
>
> -Dylan
>   
I also only backup (important) user-data, f.e. when backing up our
webserver, I backup the directories /etc, /var/www, and /home (which is
almost empty ;-)
additionaly I make dumps of all MySQL-Databases and save a list of all
installed packages.

This is mainly for restoring single files (User: "I have deleted the
file foobar, could you please restore it"), desaster-recovery would be:
1. let the provider reinstall the server (it's a rented rootserver, so
we wouldn't have access to it unless at least a base system is installed)
2. ssh to it
3. restore the backup to /tmp/restore
4. reinstall all packages from the saved list.
5. move the user-data back into place.

------------
On another system I used another aproach, which was a bit dependant on
the used linux-distribution (debian in this case, however I think rpm
would provide similar options):
1. save the list of packages ("dpkg --get-selections")
2. make a list of all files not provided by any package (a
wrapper-script around dpkg to get the list of all files provided by
packages and a "find /" for a list of all files and finally a diff of
those lists.... IIRC) or files changed from the distibuted state
(wrapper around debsums)
3. backup all files on this list.
(However I don't have this system anymore, and I forgot to save those
scripts....)

A (full-)restore whould be:
1. make a base-install
2. restore the package-list and install those packages
3. restore everything else
(the used backup-system wasn't duplicity however....)

- Tim