mounting local volume as network share

Question

I have a locally stored disk image. I would like to mount this, but have macosx think it is shared over a network (a network shared volume).

I want to do this because TimeMachine would then effectively allow me to back up to this disk image.

I tried sharing the locally mounted volume using afp, but found that macosx prevents me from mounting the volume locally since it sees that i could just access it directly.

Ideally the network share would only be accessible over the loopback interface, to prevent security issues.

Answer 1

Sven-S. Porst wrote an article about that very topic a while ago. It's a bit difficult to pull off, since you need a real AFP share to work at least once for a short time.

Starting the backup once will mark the AFP shared disk image as a valid TM target volume by adding a file (com.apple.TimeMachine.MachineID.plist) to the bundle. After that, you can convert the bundle to have encryption (if you want to have that), copy that file over to your new bundle and can enjoy the combination of local TM backups and Time Machine.