Easy. Just follow these steps:
- Obviously you need another Mac to which you want to backup to, with the disk formatted as Mac OS Extended Journaled.
- Open Terminal from Mac you want to backup from. Issue command
- Open System Preferences → Time Machine. Click Change Disk. Your network disk should appear now.
- Select it, and you are good to go.
sudo defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
