Use a Raspberry Pi 4 for Time Machine Backups (works with macOS 13 Ventura)

5 min readNov 22, 2020

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Time Machine is built into the system of macOS and I’m using it since the early days of Mac OS X Leopard. If you have a Raspberry Pi (or two) lying around at your place like me, this tutorial comes in handy to create a cheap and speedy backup solution.

Preparation

Update system software

Make sure your Raspberry Pi is running on the latest software.

sudo apt-get update && sudo apt-get upgrade

Install Samba

We’re going to first install Samba (for SMB) which is a very popular Open Source file sharing protocol which is officially supported by Time Machine for backing up data over a network. The Avahi daemon is used for Apples “Bonjour” mDNS protocol that our Raspberry Pi server is automatically discoverable within the network.

sudo apt-get install samba avahi-daemon

Storage

Connect Hard drive to USB 3.0 port

As the Raspberry Pi 4 ships with 2x USB 3.0 ports we can connect an external hard drive as our disk space for backing up data. Also we should get decent speeds as we also get a 1GBit/s wired connection with the Pi 4.

Create backup user

sudo adduser timemachine

It will ask to set a password for your newly created user.

Set a password

sudo smbpasswd -a timemachine

Create mount point

In order to mount the USB hard drive we need to create a folder where Linux can mount our device to.

sudo mkdir /mnt/timemachine

Mount device

We’ll now mount the USB drive to the previously created mount point.

sudo mount /dev/sdb1 /mnt/timemachine

Note that you’ll need to exchange /dev/sdb1 with your device

Take ownership

To allow our backup user to write on the device we’ll need to take over the ownership of the mount point:

sudo chown -R timemachine: /mnt/timemachine

Configuring Samba

Edit the Samba configuration file:

sudo nano /etc/samba/smb.conf

add the following to the end:

[backups]
    comment = Backups
    path = /mnt/timemachine
    valid users = timemachine
    read only = no
    vfs objects = catia fruit streams_xattr
    fruit:time machine = yes

This will create a network drive called “backups” which we’ll use for Time Machine.

Test Samba configuration

sudo testparm -s

If all goes well you should get an output like this

Restart service

Not let’s restart the service to make sure our changes are active.

sudo service smbd reload

Test connection to your Time Machine

On your Mac press “Command + K” on your desktop which will open the “Connect to Server” prompt. Type in the IP Address of your Pi followed by the /backups to connect to our Time Machine volume.

smb://192.168.1.150/backups

Now you should be connected to your Time Machine volume.

Configuring Avahi deamon

In order to let MacOS automatically detect our new Time Machine we’ll need to configure Avahi. For that edit the following file:

sudo nano /etc/avahi/services/samba.service

And paste this configuration in:

<?xml version="1.0" standalone='no'?><!--*-nxml-*-->
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name replace-wildcards="yes">%h</name>
  <service>
    <type>_smb._tcp</type>
    <port>445</port>
  </service>
  <service>
    <type>_device-info._tcp</type>
    <port>9</port>
    <txt-record>model=TimeCapsule8,119</txt-record>
  </service>
  <service>
    <type>_adisk._tcp</type>
    <port>9</port>
    <txt-record>dk0=adVN=backups,adVF=0x82</txt-record>
    <txt-record>sys=adVF=0x100</txt-record>
  </service>
</service-group>

With this we tell MacOS that in fact our Raspberry Pi is a 8th Gen Time Capsule and it will appear like one in the sidebar in Finder.

Restart Avahi daemon:

sudo service avahi-daemon restart

Automate things

Determine the device ID (UUID) of your USB drive

ls -lha /dev/disk/by-uuid

In my case the device was */dev/sdb1* and the UUID we’re looking for was *7efbdfc5–9c85–4e01–873a-204e00c9aa45*

Automated mount on boot via fstab

We need to tell fstab that it mounts our hard drive to the Raspberry Pi.

sudo nano /etc/fstab

Now we need to append the UUID from above like this:

UUID=7efbdfc5–9c85–4e01–873a-204e00c9aa45 /mnt/timemachine ext4 sync,noexec,nodev,noatime,nodiratime 0 0

Note: if you are using another format for your drive, don’t forget to replace it here in fstab

Automated start of the services

We need to edit crontab with:

sudo crontab -e

We’ll mount the USB drive and start the needed services on a boot/reboot:

@reboot sleep 30 && mount /mnt/timemachine && sleep 30 && umount /mnt/timemachine && sleep 30 && mount /mnt/timemachine && sleep 30 && service avahi-daemon start && service smbd start