Apples Time Machine is really a wonderfull piece of software for automating the backup process of my Macbook Pro. Networked Time Machine backup requires an AFP Volume. So I installed Netatalk on my Ubuntu desktop (which have tons of GB disk space), made a 100 GB image on it with Apples Disk Utility and pointed my Macbook to backup to that image with Time Machine. For exact details on how to accomplish this just google ‘netatalk time machine’ or something like that and you will find some howto’s.
After upgrading Ubuntu Karmic 9.10 to Ubuntu Lucid 10.04 somehow Time Machine couldn’t access the network shares anymore :|. I checked and checked and double-checked in /etc/netatalk to make sure afpd.conf and AppleVolumes.default are OK, and they were.
Browsing the shares with your Mac leaves some hidden files on your netatalk machine like .AppleDB .AppleDesktop and .AppleDouble. Not sure why but deleting these files turned out to solve the problem.
rm -r .AppleD*
Repeated this in every shared directory configured in /etc/netatalk/AppleVolumes.default