Create a Time Machine user:
sudo adduser tmuser
sudo groupadd tm_users
sudo usermod -aG tm_users tmuser
sudo smbpasswd -a tmuser
Setup a Time Machine share point:
sudo mkdir -p /var/samba/timemachine
sudo chown root:tm_users /var/samba/timemachine
sudo chmod 775 /var/samba/timemachine
Add the following lines to the end of your smb.conf
sudo vi /etc/samba/smb.conf
[global]
fruit:model = RackMac
fruit:aapl = yes
[TimeMachine Home]
comment = Time Machine
path = /var/samba/timemachine
browseable = yes
writeable = yes
create mask = 0600
directory mask = 0700
spotlight = yes
vfs objects = catia fruit streams_xattr
fruit:time machine = yes
valid users = @tm_users
Optionally, set a quota for each Time Machine share you create:
sudo touch /var/samba/timemachine/.com.apple.timemachine.supported
sudo touch /var/samba/timemachine/.com.apple.TimeMachine.quota.plist
sudo chmod 644 /var/samba/timemachine/.com.apple.timemachine.supported
sudo chmod 644 /var/samba/timemachine/.com.apple.TimeMachine.quota.plist
sudo chown root:root /var/samba/timemachine/.com.apple.timemachine.supported
sudo chown root:root /var/samba/timemachine/.com.apple.TimeMachine.quota.plist
sudo vi /var/samba/timemachine/.com.apple.TimeMachine.quota.plist
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>GlobalQuota</key>
<integer>500000000000</integer>
</dict>
</plist>
Restart the Samba service:
sudo systemctl restart smbd