As of October 2026, Proxmox Backup Server (PBS) is at version 4.2, released April 29, 2026: free, open-source (AGPLv3) backup software for Proxmox VE virtual machines and containers and for Linux hosts, with incremental, deduplicated and optionally client-side encrypted backups. Every feature, including S3-compatible object storage, off-site sync and LTO tape, works without a subscription; subscriptions cost EUR 560 to EUR 4,480 per server per year, net of VAT, and differ only in support.
More analysis lives in ET’s topic index.
In this guide
- Key facts
- How PBS works: datastores, chunks and deduplication
- What it backs up and how it plugs into Proxmox VE
- Verify, prune and garbage collection
- Off-site copies: sync jobs, S3 and tape
- Protected snapshots and ransomware controls
- Sizing and setup
- Where PBS fits in 3-2-1
- Proxmox Backup Server pricing
- PBS vs Veeam and other third-party backup
- Who it fits
- Bottom line
- Frequently asked questions
- Sources
Key facts
| Item | What Proxmox documents |
|---|---|
| Current version | 4.2 (April 29, 2026), based on Debian 13.4; PBS 3 reached end of life in August 2026 |
| License | AGPLv3; no artificial limits on storage or clients |
| Backs up | Proxmox VE VMs and containers; Linux hosts via the backup client |
| Deduplication | Chunk-based within a datastore; VM disks split into fixed chunks, typically 4 MiB |
| Encryption | Optional client-side AES-256-GCM; TLS for all client-server traffic |
| Off-site options | Sync to other PBS servers, S3-compatible storage, removable drives, LTO-5 or later tape |
| Deletion controls | Protected snapshots; a backup-only privilege that can’t delete |
| Subscription | EUR 560 to 4,480 per server per year, net of VAT; every feature at every level |
How PBS works: datastores, chunks and deduplication
PBS is client-server: Proxmox VE has an integrated client, and proxmox-backup-client covers Linux hosts. A datastore is a directory on ext4, xfs or ZFS, or a bucket on S3-compatible object storage. Per the technical overview, backups are split into chunks named by their SHA-256 checksum and stored once in the datastore’s chunk directory; every snapshot holding the same data references the same chunk. That is PBS deduplication.
VM disks are cut into fixed-size chunks, typically 4 MiB, and Proxmox VE’s dirty bitmaps track changed blocks, so only modified chunks are uploaded. File backups use dynamically sized chunks. Uploads are incremental, but each snapshot references all of its chunks, so the FAQ calls every backup a full backup.
The docs give no typical deduplication ratio, so size from your own retention and change rate. Backups encrypted with different keys can’t deduplicate against each other, the Proxmox VE storage guide notes.
Namespaces divide a datastore into a hierarchy up to 8 levels deep, so several Proxmox VE clusters or teams can share it without naming conflicts.
Client-side encryption uses AES-256 in GCM mode and is off by default. An optional RSA master key allows key recovery; without a key, the backup is unreadable. The server can check only an encrypted chunk’s CRC-32 checksum during verification.
What it backs up and how it plugs into Proxmox VE
Proxmox VE has had native PBS integration since version 6.3: add the server under Datacenter > Storage, or define a storage of type pbs on the command line, then back up guests as with any storage. The PBS docs’ example:
pvesm add pbs store2 --server localhost --datastore store2Two Proxmox VE restore features need a PBS target: live-restore, which boots a VM while data copies in the background (a failed run leaves it in an undefined state), and single file restore. Proxmox’s pricing page lists backups for all guest types, including Windows.
Outside Proxmox VE, the client runs on most modern Linux systems, with a statically linked build for any modern x86-64 Linux. It is documented for Linux only: the roadmap still lists “Backup clients for other operating systems,” along with Proxmox VE host backup.
Verify, prune and garbage collection
Per the maintenance chapter, prune jobs apply keep-last, hourly, daily, weekly, monthly and yearly rules but remove only snapshot metadata. Garbage collection (GC) frees the chunks no snapshot references, deleting only chunks untouched since a cutoff of 24 hours and 5 minutes before the run, so space frees up a run later. Proxmox suggests a weekly GC schedule to start.
The docs’ 10-year example for daily backups: keep-last 3, keep-daily 13, keep-weekly 8, keep-monthly 11, keep-yearly 9. Proxmox recommends more retention than the minimum, since pruned snapshots can’t be recreated.
Verify jobs check stored chunks against their checksums. Proxmox recommends re-verifying everything at least monthly to catch bit rot. A manual run with the default thread counts:
proxmox-backup-manager verify <datastore> --read-threads 1 --verify-threads 4 --ignore-verified falseOff-site copies: sync jobs, S3 and tape
Sync jobs. A remote is another PBS instance. Sync jobs pull a remote datastore into a local one, transferring only new data; since 3.3 they can also push, for when the remote can’t open connections to the local server. Encrypted-only and verified-only flags limit what reaches a less trusted server; remove-vanished mirrors deletions. Version 4.2 added server-side encryption for push jobs.
proxmox-backup-manager sync-job create pbs2-local --remote pbs2 --remote-store local --store local --schedule 'Wed 02:30'S3-compatible object storage arrived as a technology preview in 4.0 (August 2025) and became officially supported in 4.2. The storage docs require a local cache (64 GiB to 128 GiB recommended), leave bucket creation and access control to you, and allow only one PBS instance per datastore at a time. Proxmox warns providers may bill for storage, API requests and egress; the backup storage cost per TB analysis compares rates.
Removable datastores (since 3.3) sit on drives that can be unmounted and taken off-site, with sync jobs that start on mount and unmount when done. Tape support covers LTO-5 or later, with best-effort LTO-4, and all modern tape libraries should work. Tape data must be restored to disk before use.
Protected snapshots and ransomware controls
In Proxmox’s own terms, from the ransomware protection section and client docs:
- No rewrites: PBS “does not rewrite data for existing blocks,” so a compromised Proxmox VE host or client can’t modify existing backups.
- Least privilege: the Datastore.Backup privilege can create backups but not delete or alter them. Proxmox recommends one narrowly scoped API token per host or cluster, with pruning done on the server.
- Protected flag: a protected snapshot can’t be pruned or deleted until the flag is removed, and sync jobs don’t copy the flag. The roadmap calls it a “manual protection (immutable) flag,” but the docs describe no retention timer.
- Sync settings: leave remove-vanished off so a compromised source can’t trigger deletions on the target.
- Verification: verify jobs fail if ransomware encrypts stored backups, but Proxmox calls this an additional, not sufficient, measure.
- WORM tapes: supported with a media pool retention policy of keep.
proxmox-backup-client snapshot protected update <snapshot> trueIf policy requires retention no administrator can shorten, the PBS docs don’t describe that control; see the immutable backup storage comparison.
Sizing and setup
The system requirements:
| Component | Evaluation minimum | Production recommendation |
|---|---|---|
| CPU | 64-bit, 2 or more cores | Modern 64-bit AMD or Intel, at least 4 cores |
| Memory | 2 GB | 4 GiB plus at least 1 GiB per TiB of storage |
| OS disk | More than 8 GB | 32 GiB or more, on battery-backed hardware RAID or redundant ZFS |
| Backup storage | Not specified | High-IOPS local storage, ideally enterprise SSDs; HDDs need a metadata cache such as a ZFS special device mirror |
| Network | A network card | Redundant multi-gigabit NICs |
For a 100 TiB datastore, the memory rule means at least 104 GiB of RAM. Installing PBS on a Proxmox VE host is possible but not recommended; separate hardware keeps backups reachable if the hypervisor fails.
Proxmox Backup Server setup sequence
- Install from the ISO (ext4, xfs or ZFS; no ZFS on hardware RAID), or on Debian with
apt install proxmox-backup-server. - Open the web interface on port 8007 and add a subscription key; Proxmox doesn’t recommend the no-subscription repository for production.
- Create a datastore with GC and prune schedules.
- Add it to Proxmox VE with an API token scoped to one namespace.
- Schedule verify jobs and a sync job to a second site.
- Test restores to a new guest, never over the original.
Where PBS fits in 3-2-1
Proxmox’s docs state the 3-2-1 rule as 3 backups on at least 2 types of storage media, with 1 off-site. A placement that follows that guidance:
- Backup 1: a primary PBS on separate hardware on site, for fast restores.
- Backup 2, off-site: a second PBS pulling by sync job with remove-vanished off, an encrypted push to a less trusted site, or an S3-backed datastore.
- Backup 3, second medium: tape or removable datastores, stored offline.
The 3-2-1-1-0 rule adds an immutable or air-gapped copy and zero restore errors. Tape and removable media can supply the air gap. For the zero, Proxmox recommends regular restore tests to a new guest, automated where possible, otherwise random samples weekly or monthly; see the backup restore testing guide.
Proxmox Backup Server pricing
PBS subscriptions are priced per backup server, unlike Proxmox VE’s per-socket plans (EUR 120 to 1,100 per socket per year). Each includes every feature, unlimited storage and clients, and runs one year. As of October 2026, net of VAT:
| Plan | Per server per year | Support | Severity 1 response |
|---|---|---|---|
| Community | EUR 560 | Enterprise Repository and forum only; for non-production | None |
| Basic | EUR 1,120 | 5 tickets a year | 1 business day |
| Standard | EUR 2,240 | 15 tickets a year, remote support via SSH; 24/7 by the end of 2026 | 4 hours |
| Premium | EUR 4,480 | Unlimited tickets, remote support via SSH; 24/7 from October 19, 2026 | 2 hours |
Business hours are 07:00 to 17:00 CET/CEST on Austrian business days; from October 19, 2026, North American and APAC customers get local business hours. A primary plus an off-site server on Standard costs EUR 4,480 a year; Proxmox vs VMware covers hypervisor costs.
PBS vs Veeam and other third-party backup
Major vendors that document Proxmox VE support on their own pages:
- Veeam Backup & Replication: Proxmox VE 8.2 to 9.2 installed from Proxmox’s official ISO on x86-64, with at least one file-level storage configured.
- Commvault: Windows and Linux VMs and templates, with full, incremental and synthetic full backups.
- NAKIVO Backup & Replication: agentless Proxmox VE backup.
- Rubrik: generally available since April 21, 2026, using a backup agent on the hypervisor.
In a Proxmox Backup Server vs Veeam decision, scope is the trade-off. PBS is built for Proxmox VE, with live-restore and single file restore in the Proxmox VE interface, and a Linux-only client. Veeam and the others protect several platforms from one console, which suits mixed estates partway through a VMware to Proxmox migration. Check each vendor’s support matrix before upgrading Proxmox VE. The Proxmox enterprise-readiness scorecard and Veeam vs Rubrik go deeper.
Who it fits
- Fits: Proxmox VE estates that want deduplicated, incremental backups with live and file-level restore built in; Linux-capable teams; budgets that favor per-server pricing with unlimited storage; sites needing S3 or tape copies without extra licensing.
- Weaker fit: non-Linux physical servers; policies demanding retention locks no administrator can shorten; mixed-hypervisor estates wanting one console; 24/7 needs on Standard before the end of 2026.
Bottom line
- On Proxmox VE, evaluate PBS 4.2 first: every feature is free, and support costs EUR 1,120 to 4,480 per server per year.
- Budget two servers on separate hardware, each with at least 4 GiB of RAM plus 1 GiB per TiB and fast storage.
- Scope tokens tightly, keep remove-vanished off on off-site syncs and re-verify monthly.
Frequently asked questions
Is Proxmox Backup Server free?
Yes. It is AGPLv3 open source, and every feature works without a subscription, which adds the Enterprise Repository and, from Basic up, support tickets.
How much does a Proxmox Backup Server subscription cost?
As of October 2026, EUR 560 (Community) to EUR 4,480 (Premium) per server per year, net of VAT. Each server subscription covers unlimited storage and clients; Proxmox VE, by contrast, is priced per socket.
Does Proxmox Backup Server support S3?
Yes, officially since 4.2, after a technology preview in 4.0. A local cache is required, and providers may bill for requests and egress.
Can Proxmox Backup Server back up Windows?
Windows VMs on Proxmox VE, yes, as guest backups. The standalone client is documented for Linux only; clients for other operating systems are on the roadmap.
Are Proxmox Backup Server backups immutable?
PBS doesn’t rewrite existing chunks, backup-only tokens can’t delete, and protected snapshots can’t be pruned until the flag is removed. The docs describe no time-based retention lock.
Sources
- Proxmox Backup Server roadmap and release history
- Proxmox Backup Server subscription pricing
- PBS documentation: Introduction
- PBS documentation: Installation and system requirements
- PBS documentation: Technical overview
- PBS documentation: Backup storage and ransomware protection
- PBS documentation: Backup client usage
- PBS documentation: Maintenance tasks
- PBS documentation: Managing remotes and sync
- PBS documentation: Tape backup
- PBS documentation: Proxmox VE integration
- PBS documentation: FAQ
- Proxmox VE admin guide: Backup and restore
- Proxmox VE wiki: Storage: Proxmox Backup Server
- Proxmox VE subscription pricing
- Veeam Backup & Replication user guide: Proxmox VE platform support
- Commvault documentation: Protecting Proxmox VE VMs
- NAKIVO: Proxmox VE backup
- Rubrik blog: Rubrik for Proxmox VE is generally available
Last checked: October 2026. Prices and plans change; check the vendor’s page before you buy.
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