Apple Time Machine backup targeting Linux or Proxmox LXC

My old AirPort Time Capsule will not work with the new version of Mac OS 27 and since I really would like to have a local backup, besides iCloud, the tinkering started.

It ended up with a Linux solution and an external USB disk, 2 Tb.

In this post will show "how to" create a target for the Time Machine(TM) backup with a standard Linux host or with a Linux container in Proxmox + a Proxmox backup to the same SSD

Time Machine

Standard setup

In a Debian or Ubuntu distro you use "apt" to install Samba, filesharing, and avahi, zeroconf.

sudo apt update

sudo apt install samba avahi-daemon

and then add an user. The most convenient way is to use the same user name as in Mac OS

adduser mac_user

My USB disk is partitioned as below

lsblk

:

:

sdb   8:16   0   1.8T  0 disk 

├─sdb1    8:17   0 186.3G  0 part => Backup

├─sdb2    8:18   0   1.4T  0 part => Files

└─sdb3    8:19   0 279.7G  0 part => Time Machine

For the TM backups I created a directory

mkdir -p /mnt/timemachine

in a home server environment you can make it simple 

chmod -R 777 /mnt/timemachine 

mount /dev/sdb3 /mnt/timemachine

configure Samba with "nano /etc/samba/smb.conf" and add the following at the end

 [TimeMachine]
    path = /mnt/timemachine
    valid users = mac_user
    writeable = yes
    fruit:time machine = yes
    vfs objects = catia fruit streams_xattr

Add the "mac_user" to Samba with 

pdbedit -a mac_user

Then test configuration with "testparm -s" and restart Samba with "sudo systemctl restart smbd"

On the Mac open TM "System Settings => General => Time Machine", add the created server

and take your backup.

Proxmox LXC setup

First check that the disk is available, at node level, "Proxmox => Disks" and note their name.

In Proxmox I created a Debian LXC, container id 207, and installed Samba, avahi and added the user as above. On the Proxmox host/Node then executing the commands

mkdir -p /mnt/timemachine

chmod -R 777 /mnt/timemachine 

mount /dev/sdb3 /mnt/timemachine

pct set 207 -mp2 /mnt/timemachine,mp=/mnt/timemachine

(If you want to delete the mountpoint use "pct set 207 -delete mp2")

On the LXC guest(207) check the added disk with "df -h" and continue with

sudo apt update
sudo apt install samba avahi-daemon
adduser mac_user

Then add the Samba config as above. On the Mac add the created server and do the backup.

Mount surviving a boot

If you want to make the "mount" to survive a boot you have to add, at the host, the disk in "fstab". Get the UUID for "sdb3", in my case, with "lsblk -f", and then 

"nano /etc/fstab"and add "UUID=your-disk-uuid /mnt/timemachine ext4 defaults 0 2"

If you want to check the "fstab" entry do "umount /mnt/timemachine && mount -a"

Proxmox backup

As root, at the host, start with creating the directory "mkdir -p /mnt/pxbackups" and then

mount /dev/sda1 /mnt/pxbackups

If you want it persistant during boots check above.

Then in PX you have to add the storage

Datacenter => Storage => Add => Directory => ID:ProxmoxBackup => Directory:/mnt/pxbackups => Content:Backup => OK

In "Datacenter => Backup" set up a backup schema with the created storage and run the backup.

If you want that the "mac_user" schould have the possibility to check the backup folder via "Finder" run, at the host, "pct set 207 -mp3 /mnt/pxbackups,mp=/mnt/pxbackups" and then, at the guest, add to the Samba config

[PXBackups]

    path = /mnt/pxbackups

    valid users = mac_user

    read only = yes

    browseable = yes

    force user = root

    vfs objects = catia fruit streams_xattr

Samba remarks

Latest Samba

In Debian you can add Backports to get the latest version.

nano /etc/apt/sources.list => and add => 

deb http://deb.debian.org/debian trixie-backports main

apt update

apt install -t trixie-backports samba 

This was done due to that there been some changes in TM which is covered in the latest Samba.

Mac mounts

If a Mac mounts several shares simultaneously it could be a good idea to put "vfs objects = catia fruit streams_xattr" on the "[global]" level, in "smb.conf", and skip it in the other places.

Add-on

If you setup the TM to backup manually you can use the TimeMachineEditor to do a more granular approach.