The first step was to setup the share on linux, which was pretty straight forward as per this link Fedora 18 and OS X 10.8 Interworking using netatalk.
yum install netatalk systemctl enable netatalk
The AppleVolumes.default location was different (possibly a typo in the original post) for the fedora install I was using:
For the paths allowed, I used a more specific path:
The netatalk.conf file already contained "yes" so the last thing was to edit.
And added the suggested line
- -tcp -noddp -uamlist uams_dhx.so,uams_dhx2_passwd.so
Which is replacing the default uams_dhx2.so with uams_dhx2_passwd.so. Then I started netatalk:
systemctl start netatalk
Once this is finished I had to open a port in my firewall.
firewall-cmd --add-port 548/tcp
Then I could open the drive from my os x computer through finder->go->connect to server. I also had an issue where the hostname was incorrect, and I had to edit /etc/hostname.
After mounting the drive in os x I followed the instructions from the answer at apple stackexchange. I created a case sensitive hfs+ disk image using "disk utility" then I mounted the new volume and ran the following.
tmutil setdestination "/Volumes/MountedDmgLocation/"
Then when I opened time machine again, my new volume was the target and I could start backing up.