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Backups

This post is very out of date. The scripts which are its subject no longer exist as I now use two much simpler scripts which can be found in my scripts repo.

Backups are extremely important. In linux, with a little effort and hardrive space, one can easily come up with a fully automated backup solution to suit any needs. Here, I’d like to outline my setup. Feel free to take it and adapt to your needs.

I’ll go through what’s required, how and why I do it the way I do, as well as the shortcomings of how I’m doing it.

Requirements

My main box runs on one 500G hardrive. So far, this has suited me well even with my extensive movies and music collection. I decided I wanted to have a daily backup and a monthly backup and only one copy of each, so I went out and got a 1TB hardrive, split it, and now use that for both.

All you need is space, so whether you use an internal drive like me, an external USB, or some off-site scp/rsync situation is up to you; you’ll just have to modify my below script(s) to suit your setup.

How I do it

The first is a backup script that runs via cron daily and monthly. It can be downloaded from my git repo.

The script defines an array of files to include and another to exclude:

It takes those directories and just rsyncs them with the backup location:

/mnt/backup/daily/
|-- boot
|-- etc
|-- http
|-- patrick
|-- usr
`-- var

/mnt/backup/monthly/
|-- boot
|-- etc
|-- http
|-- patrick
|-- usr
`-- var

It also creates two text files: one that lists all your installed packages less those that are foreign (from the AUR) and another that lists those foreign packages.

These lists can be used to quickly reinstall everything you had installed at the time of the backup.

Another script I use constantly is retrieve which will take the filenames passed on the commandline and look for them in your backups. If found, the files are retrieved and re-inserted into you live system.

This is great if you’ve seriously screwed up your xorg.conf (something not in git) and you want to just roll back to what you had yesterday.

The only trick to it is that it has to handle the fact that my backup stores patrick/ at top level even though it’s /home/patrick/ on the live system.

retrieve is also no longer available in my git repo.

The last script that I have, I haven’t had to use –knocks on wood–. This restore script is intended to be used after a crash and clean re install to restore your system back from the directories made by my backup script.

You guessed it, restore is also no longer in the repo.

Why mine sucks

This solution works for me, but it has its shortcomings. Here are a few things to be aware of if you decided to implement something like what I have.

Not off-site, or even out-of-box.

If my apartment burns down, my backups are useless. To mitigate this, I’ve started taking manual copies of my monthly backup and storing them on a separate drive in a fireproof box.

Backups are not rolling

This isn’t so bad for the dailies, but my monthly backup occurs every month on the first; this means if you have an issue that’s more then two days old, and you happen to notice on the 2nd, you don’t have a backup old enough to fix it.

Untested

I’ve never had to use restore, though I do use retrieve all the time. Anyone will tell you, an untested backup solution is no solution at all. Guess I’m just too lazy to hose my install to test it. Worse comes to worst, I know the backed up data is good; if my restore script fails I can always manually copy everything over. I pretty much did this last time I installed a new Arch box; as I tend to reuse configs, just grabbing them off of my main box’s backups really sped up the process.

03 Jan 2010, tagged with linux