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Tinkergeek recently moved to its own dedicated server hosted by fdc servers. The transition wasn’t quite as smooth as one would hope, but they do provide cheap hosting. With moving to a dedicated server based around cheap PC hardware, I thought it’d be a great idea to bring back an old backup solution. Dirvish is a neat set of scripts that combine the goodness of hard-links and rsync. The goal is that Dirvish creates a full backup once and then stores just the changes of the target file system on the backup system.

Installing dirvish on a Debian system is fairly easy:

apt-get install dirvish

Then, one merely has to copy the example configuration files into place. The first one is the master configuration file that goes in /etc/dirvish and can be found in /usr/share/doc/dirvish/master.conf.

## Example dirvish master configuration file:
bank:
	/backup
exclude:
	lost+found/
	core
	*~
	.nfs*
Runall:
	root	22:00
expire-default: +15 days
expire-rule:
#       MIN HR    DOM MON       DOW  STRFTIME_FMT
	*   *     *   *         1    +3 months
#	*   *     1-7 *         1    +1 year
#	*   *     1-7 1,4,7,10  1
	*   10-20 *   *         *    +4 days
#	*   *     *   *         2-7  +15 days

Under bank: is going to be the place on your machine that contains all the backups. I’d suggest making this its own file system, as dirvish can eat inodes like there’s no tomorrow. Next, I’d suggest adding /proc and /sys under the global exclude: section just to ensure you don’t back these directories up.

Now, you have to make your first machine directory for backups (known as a vault in dirvish speak). This directory structure will be under the directory in the bank section from above.

mkdir -p /backup/example.com/dirvish

Now, just copy the default.conf example from /usr/share/doc/dirvish/examples into example.com/dirvish and edit.

client: thishost
tree: /
xdev: 1
index: gzip
log: gzip
image-default: %Y%m%d
exclude:
	/var/cache/apt/archives/*.deb
	/var/cache/man/**
	/tmp/**
	/var/tmp/**
        *.bak

The key points in this file file are the client, xdev, and exclude directives. Merely change your client: to be the machine IP or hostname that you’re backing up. Xdev tells rsync to traverse file systems on the machine; generally, you’ll want to be careful with this setting, specially if you mount NFS shares. Lastly, update the exclude list for this particular machine. If you’re backing up the local machine using dirvish, be sure to exclude the dirvish bank directory!

Now, you’re all set to create the first backup with:

dirvish --vault example.com --init

If all goes well, you’ll have a new directory under /backup/example.com with the current data and a copy of the target. If there was an error, be sure to remove the failed backup attempt from /backup/example.com and rerun the dirvish command after fixing the error.

Now, the only thing left is to run dirvish-runall via cron at some convenient time and you’re on your way to having a decent backup solution. Besure to read the remainder of the dirvish documentation to pick up the finer points of configuration.