Hello again, member of the Proxmox community. The first beta release of Proxmox Backup Server 4.0 is available!
Addendum, 7.8.25 -> Final release has already been rolled out, Even before Trixie.
This new version marks an important milestone in the development of the popular backup solution and brings exciting innovations.
Solid basis: Debian 13 ‘Trixie’
Proxmox Backup Server 4.0 is based on the upcoming Debian 13 ‘Trixie’, providing a modern and future-proof foundation. The system runs on the current 6.14.8 kernel and uses OpenZFS 2.3.3 – a combination that ensures optimal performance and stability.
The highlights of PBS 4.0 BETA
S3-compatible Object Stores (Technology Preview)
A long-awaited feature is finally here: Support for S3-compatible object stores as a backup storage backend. This feature is still in Technology Preview status, but it already enables the integration of cloud storage solutions such as AWS S3, MinIO, or other S3-compatible services.
ZFS 2.3 with RAID-Z Expansion
One of the most impressive innovations is the RAID-Z Expansion feature of ZFS 2.3. This makes it possible to retroactively extend existing RAID-Z arrays – a feature that ZFS users have been waiting for for a long time. This makes the scaling of storage systems much more flexible.
Automatic sync jobs for removable media
The new version can automatically trigger sync jobs as soon as a removable datastore is mounted. This feature greatly simplifies the workflow when using external backup media and reduces manual intervention.
Upgrade from PBS 3.4 to 4.0 BETA
Important requirements
Before you start the upgrade, you should consider these important points:
⚠ ⁇ Never upgrade via the web UI! The upgrade must be performed via SSH, a physical console or remote management (iKVM/IPMI). It is best to use a terminal multiplexer such as tmux or screen, to intercept disconnections.
Create a backup of your configuration:
tar czf "pbs3-etc-backup-$(date -I).tar.gz" -C "/etc" "proxmox-backup"At least 10 GB of free space On the root partition:
df -h /The pbs3to4 Checker – your best friend
A practical tool called pbs3to4 Helps you with upgrade preparation. Be sure to do it before upgrading:
# Basic check pbs3to4 # Full Check (recommended) pbs3to4 --fullThe script checks your system and warns of possible problems. After each correction, do it again to make sure that the issues have been fixed.
Maintenance Mode (optional but recommended)
To reduce I/O load during the upgrade, you can put your datastores in read-only mode:
# Enable read-only mode proxmox-backup-manager datastore update DATASTORE-ID --maintenance-mode read-only # After upgrade disable again proxmox-backup-manager datastore update DATASTORE-ID --delete maintenance-mode
Repository conversion step by step
1. Check current version:
apt update apt dist-upgrade proxmox backup manager versionsYou should have at least version 3.4.2-1.
2. Switching Debian repositories to Trixie:
sed -i 's/bookworm/trixie/g' /etc/apt/sources.listAlso check all files in /etc/apt/sources.list.d/ and comment on Bookworm repositories with # off.
3. Add PBS 4.0 BETA Repository:
cat > /etc/apt/sources.list.d/pbs-test-for-beta.sources << EOF Types: deb URIs: http://download.proxmox.com/debian/pbs Suites: trixie Components: pbs-test Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg EOF4. Remove or disable old PBS 3.x repositories
With apt policy You can check if all repositories are recognized correctly.
The real upgrade
apt update apt dist-upgradeImportant information during the upgrade:
- Schedule time: Depending on the hardware, the upgrade takes 5-60 minutes
- Configuration files: For requests for configuration changes:
/etc/issue: ‘No’ (keep current installed version)/etc/ssh/sshd_config: For standard setup “Yes” (package maintainer version)/etc/default/grub: Carefully check for own changes, otherwise ‘No’
Be sure to restart after the upgrade:
systemctl rebootPost-upgrade checks
Check services:
systemctl status proxmox-backup-proxy.service proxmox-backup.serviceClear browser cache: CTRL + SHIFT + R (or macOS: (cauliflower button) aka Cmd + Alt + R)
Disable Maintenance Mode (if activated)
Possible problems and solutions
Older hardware
For hardware older than 10 years, extensive testing before the production upgrade is recommended. The new 6.14 kernel could cause compatibility issues.
Network interface names
Better hardware detection can change interface names. Make sure you have physical or remote access (IPMI/iKVM) to the console.
ZFS on Root with UEFI
For ZFS root systems with UEFI, you may need to systemd-boot Install package manually. This pbs3to4 Script warns you if your system is affected.
Important Warnings for Beta Users
⚠ ⁇ Not suitable for production environments! The beta version does not receive security support and may have instability. Use only in test environments.
✅ Upgrade to the final version possible: Once PBS 4.0 is stable, you can easily upgrade from the beta to the final version.
Repository Configuration for New Installations
For fresh installations of the beta version:
deb http://download.proxmox.com/debian/pbs trixie pbs-testOutlook and Roadmap
The beta version is continuously supplied with updates, bug fixes and new features. A specific date for the final release has not yet been set – stable version 4.0 will be available once all critical bugs are fixed and the new features are classified as stable.
conclusion
Proxmox Backup Server 4.0 BETA is a promising development with future-oriented features. Especially the S3 integration and the RAID-Z expansion function should inspire many administrators.
The upgrade is technically demanding and requires careful preparation. This pbs3to4Tool helps to identify problems in advance. Plan enough time and provide alternative access routes to your system.
Finally, all the important links:
Have you had any experience with the beta? Share your impressions on the forum!
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