Though, Tony already posted the magic command to make non-local volumes (connected through smb, nfs or afp) visible to Time Machine, I want to give a brief description on how I configured Time Machine on my MacBook Pro to use a Windows share.
1. First let’s make sure the volume isn’t already mounted:
2. Now mount the Windows share in Finder (Command (Apple) – K):
3. The Windows share will appear in the ‘Shared” section in Finder:
4. To verify, open Terminal and check the mounts:
5. Enter “defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1″ in the Terminal window to make unsupported network volumes visible to Time Machine:
6. Now you can configure Time Machine (System Preferences -> System -> Time Machine):
7. Done. Time Machine is now ready to backup your data…
8. …unfortunately there is not enough space on the Windows share 😉
9. But at least you can see that Time Machine tried its best:
BTW, with “defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 0” you can revert the setting.