RFC: Backup of system data
Hi,
inspired by a mail in debian-user-de, I think you should implement a
system to ease the backup of important system data.
I know there was an attempt for a dbackup, and its specs (comparing
the content of the disk with the contents of the deb files, thous
automatically detecting the files for backup) are technically to best
solution, but I believe this is not doable.
The reason:
You need some source for the packages you installed.
- CD: slink doesn't fit on one CD already, so you need either a
changer, more drives or you have to change CDs manually
- NFS Mirror / FTP: What about packages on hold, which have a newer
version on the mirror? We also have to download the packages. What if
you don't have diskspace for doing this?
Furthermore, extracting the packages and comparing them takes long and
needs really some cpu power. For the one of us who don't have rather
old boxes as servers, this is a important fact.
An alternative way is this:
It is sufficient to backup /etc/ and some important data outside of
/etc/ like /var/lib/dpkg/ or links in /etc/ pointing to somewhere
outside the tree (except it is static data like /etc/localtime).
If a package stores important data outside os /etc/, it mentions it in
a file:
/etc/dbackup/bind:
/var/named/
/etc/dbackup/dpkg:
/var/lib/dpkg/
/etc/dbackup/isdnutils:
/var/spool/vbox/
In these examples, I just list directories, but you can also name
files.
And the admin can also add his own local data to this.
/etc/dbackup/local.webtree
/var/www/
The /etc/dbackup/* files would be conffiles.
The actual backup:
tar cfvz backup.tar.gz /etc/ `cat /etc/dbackup/*`
Now you have a backup of all your important data.
Of cause you can place a nice GUI around this (selecting the files in
/etc/dbackup to use, where to put the backup [ file, upload via ftp,
direct creation on another host via ssh ...] or other things).
You want to use the fancy xyz programm for doing the backup? I believe
any programm can read the list of dirs and files you can easily create
from the /etc/dbackup/* files.
The good thing is, that it is a flexible approach, it uses standard
unix matters (pipeable input etc.), and the user doesn't have to hunt
down the important files outside of /etc/ himself. The
package maintainer has better knowledge about it.
I don't think any other Linux distribution has such a system at all.
For this thing to work, there need to be a policy, that packages have
to supply a file in /etc/dbackup/ if they store config data outside of
/etc/, right?
What do you think? Is it worth it? Any seconders? Should this be taken
to debian-policy?
Ciao,
Martin
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