I backup my MacBook using Time Machine. But the storage is available from a Linux (Ubuntu 16.04) workstation. Here’s how to publish some storage to provide backup space to the Mac.
First of all, the storage space has to be published as an AFP file share. This is done using Netatalk ; a freely-available Open Source AFP fileserver.
# sudo apt install netatalk
Then, configure the share by adding its reference.
# sudo vim /etc/netatalk/AppleVolumes.default (...) /volume/external/TimeMachine "Time Machine" allow:user1 options:tm,usedots,upriv
And restart the service
# sudo service netatalk restart
From there, start the Time Machine preference panel. Select the drive and go-go-go!
PS: Not sure how this matters but I had “Show Unsupported Network Volumes” configured ; while trying to set up Time Machine over SMB. The Mac command line was:
# defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1