Proxmox Backup Server 3.4 is now available, delivering a suite of enhancements aimed at optimizing performance, expanding flexibility, and improving usability for modern backup and disaster recovery strategies. Building on the foundation of previous releases-such as the push-to-remote datastore feature in 3.3-this update further cements Proxmox's reputation as a robust, enterprise-ready open source backup solution.

Key Highlights of Proxmox Backup Server 3.4

Optimized Garbage Collection (GC) with Caching

  • Faster Cleanup: The garbage collection process, which reclaims space by deleting unreferenced backup data chunks, now leverages a caching mechanism. This reduces the number of expensive file metadata updates, substantially speeding up GC runs-especially in environments with many backups and heavy deduplication.
  • Configurable Performance: The caching mechanism can be fine-tuned per datastore, allowing administrators to balance memory usage and GC speed according to their needs.
  • Result: Shorter GC runtimes and improved efficiency, particularly for large-scale or high-churn backup environments.

Granular Sync Job Filters

  • Enhanced Offsite Backup Control: Sync jobs can now filter not just by backup group, but also by snapshot status-enabling exclusive synchronization of only encrypted or verified backup snapshots.
  • Security and Compliance: This makes it easier to automate offsite or multi-site backup workflows that comply with organizational security or integrity requirements.
  • Use Case: Perfect for organizations needing to replicate only secure or validated data to remote locations.

Static Build of the Proxmox Backup Client

  • Portability: A new statically linked command-line client is available, making it simple to run file-level backups on any Linux system-even outside the Proxmox VE ecosystem.
  • No Dependency Hassles: This portable binary eliminates the need for shared libraries, streamlining deployments on diverse Linux distributions.

Increased Tape Backup Throughput

  • Parallel Processing: Administrators can now increase the number of worker threads when reading chunks during tape backups, boosting throughput and speeding up large-scale tape operations.
  • Efficiency: Especially beneficial for organizations relying on tape for long-term, high-volume archival storage.

Updated Platform and Hardware Support

  • Modern Base: Built on Debian 12.10 (“Bookworm”), with Linux kernel 6.8.12-9 as the default and optional kernel 6.14 for the latest hardware compatibility.
  • File System: Ships with ZFS 2.2.7, including compatibility patches for newer kernel versions.

Improved Web Interface and Stability

  • UI Enhancements: The web UI now offers more customization (e.g., default login areas) and improved tools like a more flexible prune simulator for retention policy planning.
  • Robustness: Better handling of filesystem timestamps and a modernized internal locking system increase stability, especially on networked datastores and in high-availability setups

Integration and Upgrade Path

  • Proxmox VE Integration: Seamless-just add a Proxmox Backup Server datastore as a backup target in Proxmox VE (version 8.4 or later recommended).
  • Upgrade: Existing installations can upgrade via APT; detailed instructions are available in the official documentation.
  • Compatibility: Active compatibility testing ensures smooth operation with supported Proxmox VE and client versions. Older clients are supported on a best-effort basis.