This is how I run Borg on TrueNAS Core.

Create a jail

1. Add a Borg group and user account to TrueNAS Core:
   • Username: borg
   • Group: borg
   • Disable password: Yes
   • Shell: nologin
2. Create a dataset to store the Borg repositories: /mnt/tank1/backups/borg
3. Create a new jail named borg
   • Give it a static IP address so that other hosts on the network know where to connect for backups
4. Mount /mnt/tank1/backups/borg to /backups within the jail
5. Start the jail
6. Open a console to the jail (iocage console borg or via the TrueNAS UI) and carry out the rest of these steps within the jail

Set up the jail

# Install prerequisites
pkg update
pkg install python38 py38-borgbackup

# Enable the SSH server
sysrc sshd_enable=YES

# Add a Borg group
pw group add borg -g <same GID as the Borg user you created in TrueNAS>

# Add a Borg user
pw user add borg -u <same UID as the Borg user you created in TrueNAS> -d /backups -g borg -s /bin/sh

# Give the Borg user ownership of the backup repositories
chown borg:borg /backups

# For each backup client, add its SSH public key to the Borg user's authorized_keys
echo <client SSH public key> >> /backups/.ssh/authorized_keys

Now you should be able to back up to this jail using Borg on each client, using a repo name such as borg@borg:/backups/REPONAME. Don’t forget to add SSH public keys for any new clients.

Resources

• Borg installation