Proxmox Backup Server 4.2 Adds S3 Support Improved Sync Control and Linux Kernel 7.0

Proxmox introduced the new version Proxmox Backup Server 4.2, based on Debian 13.4 Trixie. The update includes updated packages, improved hardware support, and new security updates from the base system.

Version 4.2 transitions to Linux kernel 7.0 as the default kernel and includes ZFS 2.4 for environments using ZFS-based infrastructure.

The new release focuses on better organization of backup environments, improved security for sync processes, higher data transfer performance, and official support for S3 storage.

More flexible management of backup data

With Proxmox Backup Server 4.2, administrators can now move backup groups and namespaces to different locations within a single datastore. This enables easier reorganization of backup structures without the need for re-copying data or building new backup environments.

The process uses a locking mechanism for individual backup groups to ensure data consistency during the move, including for large or actively used backup sets.

Improved security for sync tasks

Version 4.2 adds server-side encryption and decryption capabilities for sync tasks.

Push sync processes can now automatically encrypt snapshots when sending them to a remote datastore, which is useful when synchronizing to less trusted Proxmox Backup Server instances.

Pull sync tasks also support automatic decryption of snapshots encrypted on remote systems. In addition, encryption key management is centralized, with tape and sync keys now managed through a unified interface.

Higher performance during synchronization

Proxmox Backup Server 4.2 introduces parallel processing of sync tasks through the new worker-threads property. This allows multiple backup groups to be processed simultaneously and improves performance in high-latency environments where serial processing may slow down transfers.

The update also addresses limitations in HTTP/2 connections by enabling parallel execution of sync processes across different backup groups.

Logging has also been improved through:

• contextual prefixes for log messages
• better visibility into push sync activity
• easier tracking of issues and sync operations
  
  

Official S3 support

One of the most significant new features is official support for S3-compatible object storage as a backend for backup environments.

This allows S3-based datastore solutions to be used as a fully integrated part of backup strategies in Proxmox environments.

Version 4.2 also adds:

• request counters
• traffic statistics for S3 datastore systems
  
  

These metrics are displayed directly in the datastore summary panel and help administrators monitor traffic and detect unusual activity earlier.

Availability and support

Proxmox Backup Server 4.2 is available as a full ISO image for direct installation on bare-metal systems via a guided installer.

Existing installations can be upgraded through the standard APT package system, and the platform can also be installed on an existing Debian environment.

The software is distributed as Free/Libre Open Source Software under the GNU AGPLv3 license. Proxmox also offers enterprise subscription plans starting at €560 per server per year. The subscription includes:

• unlimited backup storage and clients
• access to the Enterprise Repository
• web interface updates
• certified technical support