I've got tons of satellite images and GIS data that I don't want to loose. But hard drives are not eternal.

My home made backup system is a simple external usb2 hard drive: PC hard drive are becoming cheap, and you can by for some bucks an usb2 external case to plug it in. Now, the question is only how to manage that.

On any *nix system (Unix, Linux, Mac OS X, ...) you can use rsync to make a fast backup of your repositories.
My backup hard drive is mounted on /Volumes/Archive on my Mac.
I wrote a very simple bash script:

#!/bin/sh -l
rsync -E -a -x -S --delete --progress --exclude-from=/Users/bubuitalia/exclude_from_rsync.txt /Users/bubuitalia /Volumes/archive/save

This script was saved in my home directory (/Users/bubuitalia) as backup.sh (do not forget to do a chmod u+x backup.sh this script to make it executable). You just have to change the path for your own installation. To run it, type ./backup.sh

This rsync command synchronizes the data in /Users/bubuitalia/ with the archive directory (/Volumes/archive/save).
The rsync commands line has the following options:

  • -E : copies extended files attributes.
  • -a : archive mode
  • -x : don't cross file system boundaries (omits all mount-point directories from the copy)
  • -S : try to handle sparse file in an efficient way
  • --delete : delete extraneous files on the receiving system: if you delete something on your original data set, it will be deleted on the archive at the next synchronization. Use this function if you want to maintain a mirror copy of your system. It is worth to use it to avoid your archive size to get too large with time.
  • --progress : show progress during transfer.
  • --exclude-from=FILE : read exclude pattern from FILE

Don't forget: if you run the script, any change in the original data will be applied to the backup. So, if you delete a file and want to restore it, do not run the script! First retrieve the data from the archive (any data deleted on the source, will be deleted on the archive after each synchronization).

I made another file, /Users/bubuitalia/exclude_from_rsync.txt, where I listed (1 entry per line) the directories I don't want to save:

Music/
Movies/
Library/Caches/
.Trash/

To adapt this example to your own system, simply change the source and target directories.
The rsync page is on http://rsync.samba.org/
and you can find some other examples on http://rsync.samba.org/examples.html