I have never done a backup despite having had my iMac G5 for about 7 months. One of the reasons for this is I do not have an external disk. I realised I could backup to DVDs but have been put off by the hassle of organising my data in such a way that it fits into neat amounts that each fill a DVD. Of course I'm sure there are plenty of great software applications I could buy that would make things easier, but it occurred to me that since MacOS X is UNIX based I probably have all the tools I need to do a backup (or I could at least get them for free).
After a bit of thinking, I figured tar was probably the best option, since it allows for multi-part backups with the -M switch. Though I soon realised (after a few web searches) that the versions of tar included with Panther (my current OS) do not understand resource forks, and this could potentially cause me problems further down the line, should I need to restore (Tiger's tar does support resource forks).
A bit more searching on the web and I stumbled across hfstar and xtar, which are both variants of GNU tar, but do support resource forks (although they store the resource forks inside the tar in different ways, and are hence incompatible). In terms of features, there is nothing to choose between them; they do exactly the same thing. There was mention on one website that author of the page had encountered some errors with hfstar and switched to xtar (which fixed the issue). To be fair though this could be related to old problems that have since been fixed. Also there seems to be a greater number of people recommending hfstar than there are xtar (though this could be related to the fact that it seems to be older). I recommend you test both and see which works for you. I decided to go with xtar first but might try hfstar next time.
Anyway, below I have outlined the method I used to do the multi-DVD backup (it would also work with CDs). Feel free to change the instructions to make use of hfstar instead if you prefer. Or if you are a Tiger user, you can simply use the tar program provided. I would not advise using one version of a resource fork capable tar (hfstar, xtar, or Tiger tar) to back up and another one to restore. My understanding is that they all support resource forks in incompatible ways, so whatever you use to back up, you should also use to restore!
Here is the method:
$ cd /
$ sudo xtar -cvpMf /Volumes/multipartdvdbackup/backup.tar Users/
Here is a breakdown of what the switches mean:
$ cd /
$ sudo xtar -xvpMf /Volumes/multipartdvdbackup/backup.tar
The -x flag tells xtar to extract the files from the archive.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050609093101245