Meh, I struggled to get my pi to work as a time machine server. It would work for a few weeks and then just stop working and I would have to start the backup from scratch previous backups becoming unusable.
In the end I just plugged an external hard disk into the mac.
I have had similar issues in the past even with such simple things as SSH to a Mac. It would be easy to blame the pi or Linux, but as far as I can tell, Apple just does not play nicely with anything not Apple. It's just that little bit different. I have no such problems interfacing Linux and the pi with anything else.
In the end I just plugged an external hard disk into the mac.
I have had similar issues in the past even with such simple things as SSH to a Mac. It would be easy to blame the pi or Linux, but as far as I can tell, Apple just does not play nicely with anything not Apple. It's just that little bit different. I have no such problems interfacing Linux and the pi with anything else.