1) Modify system preferences by executing this line in a terminal.

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1


This will allow you to select the DNS as a backup device when you configure Time Machine.

2) You need to manually create a disk image that Time Machine can understand. The naming convention of this image is key. The name consists of the computers name and mac address of the local eno device without colons. (_.sparsebundle). Easiest way to find out the proper name is to attempt a backup after completing step 1 above. While this is attempting to run, use finder to browse the Volume (Volume_1 in my case) and write down the name of the file its trying to create. The filename will contain .tmp before the .sparebundle. Drop this from the filename and you have the complete name you need to use.

ie: gataca_0021413a0cce.tmp.sparsebundle -> gataca_0021413a0cce.sparsebundle

Open disk utility and create a new disk image on your local drive (you cannot create the image directly on the NFS drive) with the following options:

Format: Spare Bundle Disk Image
Partiions: No Partition Map
Encryption: None
Format: Mac OSX Extended Partition (Journaled)
Size – Maximum Size.. I choose Custom 250GB

After the image is created… manually copy it over to the root of your NFS volume.

3) Kick off the time machine backup and voila!

Now.. be prepared for the caveats of this solution mentioned here.