Proxmox Backup Server 3.x to 4.x Upgrade

Arslan GÜRALLinux, Proxmox Backup Server1 week ago547 Views

Proxmox Backup Server 3.x to 4.x Debian 13 (“Trixie”) Upgrade Guide

This guide covers the migration from Proxmox Backup Server 3.x to 4.x and upgrading your system to Debian 13 (Trixie).

1. Preparation and Warnings

WARNING: To prevent any data loss, back up all critical PBS configurations and backups to an external location before starting. If possible, test your backups!

Proxmox PBS 4.x runs on Debian 13 (Trixie). PBS 3.x runs on Debian 11/12.
Pause all backup tasks, client connections, and critical jobs during the upgrade.
Connect to your server via SSH and make sure you have root privileges.

2. Maintenance Mode & Checklist Script

Optional: Enable Maintenance Mode
To block client connections and new backup/restore jobs during upgrade, you can enable maintenance mode:

proxmox-backup-manager maintenance enable

To disable maintenance mode after the upgrade:

proxmox-backup-manager maintenance disable

2.1. Use the “pbs3to4” Checklist Script Before Upgrading

The latest Proxmox Backup Server 3.4 comes with a tool called pbs3to4. This script checks for potential issues before, during, and after the upgrade.
The script only checks and reports problems; it does not make any changes to your system!

Basic usage:

pbs3to4

To run with all checks enabled:

pbs3to4 –full

Note: Always run pbs3to4 --full at least once before the upgrade. After fixing any reported issues, re-run the script to ensure they are resolved.

3. Update & Backup Your System

3.1 Update Your Current System

apt update
apt upgrade -y

3.2 Backup Configurations and Critical Files

cp -a /etc/proxmox-backup /root/backup-proxmox-backup-etc/
cp -a /etc/systemd/system/proxmox-backup* /root/backup-proxmox-backup-systemd/
cp -a /etc/fstab /root/backup-fstab

Tip: Always store your backups on a separate server or NAS for extra safety.

4. Update to Debian 13 “Trixie” Repositories

Replace all “bookworm” entries with “trixie” in your main sources list:
```
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list
```
Update all .list files under /etc/apt/sources.list.d/ as well:
```
sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/*.list
```
Disable or replace any old Bookworm repositories:
```
grep bookworm /etc/apt/sources.list /etc/apt/sources.list.d/*.list
```
Comment out (#) or update all Bookworm lines to use “trixie”.

Example repository entries for PBS 4.x:

deb http://deb.debian.org/debian trixie main contrib
deb http://deb.debian.org/debian trixie-updates main contrib
deb http://security.debian.org/debian-security trixie-security main contrib
deb http://download.proxmox.com/debian/pbs trixie pbs-no-subscription

For enterprise users:
deb https://enterprise.proxmox.com/debian/pbs trixie pbs-enterprise

5. Full Upgrade to Debian 13 (“Trixie”)

Update the package list:
```
apt update
```
Start the distribution upgrade:
```
apt dist-upgrade
```
Complete all upgrades:
```
apt full-upgrade
```
Clean up unnecessary packages:
```
apt --purge autoremove
apt clean
```
Reboot your system:
```
reboot
```

6. Upgrade Proxmox Backup Server Packages to 4.x

Upgrade PBS packages:
```
apt update
apt upgrade -y
```

Check service status:

systemctl status proxmox-backup-proxy.service
systemctl status proxmox-backup.service

Verify your version via the web interface or using proxmox-backup-manager.

7. Final Checks & Testing

Test your backup jobs and storage connections in the PBS web UI.
Ensure all network and automation features work as expected.
If there are no errors or missing files on your storage mounts, your upgrade is complete.
After the upgrade, run pbs3to4 --full again to check for any remaining warnings.

8. Troubleshooting & Rollback

If any service fails to start, check journalctl -xe and /var/log/syslog for errors.
Restore your previously backed-up configuration and system files if needed.

If you encounter problems or service downtime during the upgrade, you can roll back using your full disk/configuration backups.