Logiciel Libre

My data is important. Enough so that I’ve hemmed and hawed for quite a while over the best automated backup solution. I started out with tar, then moved on to rsync. Now I’m keen to rsnapshot. Here’s a Zod-focused guide to setting it up.

Installation

$ sudo yum install rsnapshot

Sweet.

Configuration

Here’s /etc/rsnapshot.conf:

config_version	1.2

# a second local hard drive is mounted at /backup
snapshot_root	/backup/snaps

cmd_cp			/bin/cp
cmd_rm			/bin/rm
cmd_rsync		/usr/bin/rsync
cmd_logger		/usr/bin/logger
cmd_du			/usr/bin/du
cmd_rsnapshot_diff	/usr/bin/rsnapshot-diff

interval	hourly	4
interval	daily	7
interval	weekly	4
interval	monthly	3

verbose		2
loglevel	3
logfile		/var/log/rsnapshot.log
lockfile	/var/run/rsnapshot.pid

link_dest	1

exclude	/backup
exclude	/dev
exclude	/lost+found
exclude	/media
exclude	/mnt
exclude	/proc
exclude	/sys
exclude	/tmp
exclude	/var/cache/yum/*

backup	/	localhost/

# vim: ft=config noet nosta

(the whitespace must be tabs, not spaces)

I also created a log rotation config file, /etc/logrotate.d/rsnapshot:

/var/log/rsnapshot.log {
	missingok
	notifempty
}

Testing

$ sudo rsnapshot configtest
Syntax OK

$ sudo rsnapshot -t hourly
# ...snipped...
# (worked)

$ sudo rsnapshot hourly
# (worked)

Done. Ready to add this thing to root’s crontab.

# 4 hourly backups a day (once every 6 hours, at 0,6,12,18)
0 */6 * * * rsnapshot hourly

# 1 daily backup every day, at 11:50PM
50 23 * * * rsnapshot daily

# 4 weekly backups a month, at 11:40PM, on the 1st, 8th, 15th, and 22nd
40 23 1,8,15,22 * * rsnapshot weekly

# 1 monthly backup every month, at 11:30PM on the 1st day of the month
30 23 1 * * rsnapshot monthly

Pros

• bundled with Fedora Core 6
• FLOSS (of course)
• simple and maintainable
• fast (enough): hourlies take about 3min to run
• training, setup time seemed reasonable
• nicely automated, set and forget (hopefully)
• efficient use of disk space, no compression needed

Cons

• can’t just say “backup /”. Special dirs like /proc and /sys must be avoided
• can’t use backup to create a new bootable disk (although I’d probably want to rebuild rather than restore, anyway)
• no compression (but I don’t currently need it)
• no encryption (but this is just a local backup, DIBS will probably be used for remote, encrypted backup)
• extra work must be done to back up MySQL databases, bdb-backed Subversion repositories, etc. (but backup scripts are supported by rsnapshot)

All of the cons are simply due to lack of features. However, the features that are included work quite well!

One other thing I’m not sure of is if/how rsnapshot recovers from crashes.

Other reading material:

• Backing up UNIX(-like) filesystems
• Lessons learned from large-scale computing environments