Learn Proxmox Backup Server - PBS 4.2 & Latest Features

#Introduction

After episode 16 trained you to handle problems, now it is time to look at PBS's present: the version running today and the features that just arrived. In 2026, PBS sits at 4.2 — a release that brings a new Debian foundation and the most awaited feature: S3 object storage support.

The analogy is like renovating an archive warehouse: the foundation is replaced (new Debian), the recording system is upgraded (ZFS 2.4), and a new storage wing is added in the cloud building (S3). The old warehouse is still in use, but its capacity and flexibility have jumped.

#PBS 4.2: The Current Release

#When and What's New

PBS 4.2 was released April 29, 2026 as the current stable release. The 4.2 number marks the second minor release of the 4 series — fixes and feature additions on top of the PBS 4 foundation released August 6, 2025, without architectural changes that force a configuration overhaul.

Verify the version you are running:

Check the PBS version

proxmox-backup-manager versions
proxmox-backup-server --version

#The New Foundation: Debian 13.4 Trixie

PBS 4.2 stands on Debian 13.4 (Trixie) — a newer system base than the 3 series, which still used Debian 12 (Bookworm). The practical impact:

Proxmox kernel 7.0: the latest Proxmox kernel brings new-generation hardware support and I/O path performance improvements used by backups.
ZFS 2.4: a far newer ZFS version — important because most PBS datastore best practices (episode 15) are built on ZFS.
Fresher toolchain, network drivers, and system libraries, following the Debian release model: new Debian stable → new PBS major.

#Headline Feature: S3 Object Storage

#Datastore on Top of S3

The headline feature of PBS 4.2 is S3-compatible object storage support as a datastore backend. A datastore no longer has to be a local filesystem (ZFS/ext4) or an NFS/SMB mount — you can create a datastore that stores chunks in an object storage bucket (AWS S3, Backblaze B2, Wasabi, MinIO, and others).

The benefits are immediately felt for off-site scenarios (episode 10):

An off-site location without managing a second PBS server.
Capacity follows needs without manual disk provisioning.
Integration with S3 Object Lock for an immutable anti-ransomware layer (episode 14).

Tip

S3 object storage is best suited as an off-site destination, not a replacement for the primary local datastore. S3 latency is far above local disks, so daily backups remain ideal on local ZFS; S3 becomes the outer layer for sync and extra protection.

#Creating an S3 Datastore

From the CLI, an S3-based datastore is created by specifying the endpoint, bucket, and credentials:

Create a datastore on an S3 bucket

proxmox-backup-manager datastore create store-s3 \
  --storage s3://bucket-pbs/offsite \
  --access-key-id 'AKIA...' \
  --secret-key '...'

Chunks, dedup, and snapshots work exactly like a local datastore — PBS just swaps the "paper" it writes on. Verify and GC schedules (episodes 6 & 9) still apply.

#Proxmox VE 8.x/9.x Integration

PBS 4.2 remains the true partner of Proxmox VE: integration covers PVE 8.x and 9.x. The episode 4 flow (add PBS as storage, backup, restore) is unchanged — including guest agent support, snapshot/suspend/stop modes, and backup schedules.

With S3, an interesting new pattern emerges: PVE writes to the local PBS datastore, then PBS syncs to S3 — without a second PBS server. This "fast local + cloud off-site" combination is the direction the roadmap wants (episode 21).

#Release History & Support Model

#The PBS 3.x → 4.2 Road Map

3.x (2023-2025): the 3 series introduced datastore namespaces and various operational refinements.
3.4 (April 10, 2025): the closing release of the 3 series.
4 (August 6, 2025): a major jump with a new Debian base.
4.2 (April 29, 2026): the current release with S3 object storage.

#Security Support

Important to remember: PBS 3 security support ends August 31, 2026. If you are still running the 3 series after that date, you will no longer receive security patches. Plan the upgrade before the deadline, not after.

#The Upgrade Path

Upgrading from 3.x to 4.2 (or 4.x → 4.2) follows the standard apt flow:

Upgrade PBS via apt

apt update
apt list --upgradable
apt dist-upgrade
proxmox-backup-manager versions

Mandatory steps before upgrading:

Snapshot/back up the PBS system — the datastore is data, but the operating system and configuration need backups too.
Read the release notes at pbs.proxmox.com/docs/release-notes.html for changes affecting configuration.
Do it in a maintenance window, one node at a time if there are multiple PBS servers.

Warning

Do not upgrade PBS in the middle of a backup window, and never skip a system snapshot before upgrading. Distinguish "data" (chunks in the datastore) from "system" (OS + configuration) — both must be safe, because a failed upgrade will stop the entire PVE backup pipeline.

#Closing

Key takeaways:

PBS 4.2 (April 29, 2026) is the current release: Debian 13.4 Trixie, Proxmox kernel 7.0, ZFS 2.4.
Headline feature: S3 object storage — datastore on an S3-compatible bucket, ideal for off-site.
PVE 8.x/9.x integration is unchanged; the new "local + sync to S3" pattern enriches the architecture.
History: 3.x (2023-2025) → 3.4 (Apr 2025) → 4 (Aug 2025) → 4.2 (Apr 2026).
PBS 3 security support ends August 31, 2026 — upgrade before the deadline.
Verify with proxmox-backup-manager versions and read the release notes before upgrading.

In the next episode, episode 18, we will scale: many datastores on one server, organizing clients and groups, hub-spoke architecture via remote sync, and capacity planning calculations — dedup ratio, bandwidth (10G recommended), and disk sizing. From one PBS to a structured backup infrastructure!