AppleTalk for naught
I've spent more than one evening getting Time Machine (the Mac OS X built-in backup solution) to work with our Linux box. It works fine over samba, but the hitch is that you can not do a disaster recovery as the Mac OS X install DVD can not connect to samba servers in order to restore your system.
The solution, of course, is to use AppleTalk instead. I'd read that the new Mac OS versions require SSL support with netatalk. I've found thousands of pages on how to enable compile-time SSL support on Debian and Ubuntu, and they both used distributor-provided built options that were not available to me on Fedora, and the vanilla netatalk source uses OpenSSL just and only to encrypt passwords.
So I've searched the net for newer netatalk versions or SSL patches, or for details on what the Debian package manager had done to enable SSL. After several hours I had learned that they didn't do anything. "SSL support" referred only to the crypted passwords, right from the start, and I've had a working netatalk all along as Fedora has it pre-compiled with SSL.
After getting netatalk and avahi (a kind of network service announcer for Macs) to work I was able to see my Linux server pop up automatically on Mac OS.
That's when the Time Machine trouble started. Connecting to the same Linux server with both samba and netatalk is obviously something that Mac OS does not do very well. I've had corrupted hidden Mac special files on my backup volume and seen all kinds of difficulties. Long story short, I've tried every combination I could think of, but in the end I was just glad that Time Machine would work over samba again. At no point was I able to use the backup in the system recovery tools, which was why I had started the whole AppleTalk thing anyway. I could connect to the AFP server from the booted install DVD, but Time Machine wouldn't let me pick the share as a data source.
At that point, analyzing the problem further would have required substantial effort. I didn't feel like investing another evening into detailed network traffic analysis and finding a way to run-time trace the Mac OS X install DVD.
So I ditched netatalk and went back to samba only. Now everything works as before, Time Machine happily makes backups, I can restore fine as long as it's not a total system crash recovery, and should I ever need one of those I'll simply have to copy the entire Time Machine data onto an external disk first.
So that's roughly two evenings of fiddling with nothing to show for. On the other hand, that's how it sometimes goes in IT, and along the way I've learned one thing or another about a number of topics.