Proxmox Backup Server: Open-Source Backup Ledger 2026

Part of the Open-Source Backup Ledger (edition 2026-10-02). How the scores work: methodology.

Snapshot

Kind: Backup platform
Licence: AGPLv3; every feature in the open-source release
Backer: Proxmox Server Solutions GmbH (Vienna), privately held and profitable
Paid edition or support: Per-server subscriptions EUR 560 to 4,480 a year (published); 24/7 support from 2026-10-19
Latest release: 4.2, 2026-04-29
Next signal: Roadmap: Proxmox VE host backup, native Windows and macOS clients, Datacenter Manager integration
Archetype: Ecosystem-bound platform, dependable builder
Evidence grade: A. Release history, roadmap wiki and prices read from Proxmox sources; dates match the VM Ledger research.

Scope of the scores: PBS did not exist before its 2020 beta, so history starts in 2020.

Scorecard

Dimension	Score	Direction
Capability today	70.6 / 100	higher is better
Momentum since end of 2022	+4.0 points	higher is better
Credibility	21.0 / 25	higher is better
Sustainability risk	7.0 / 25	lower is better
Technical lock-in	7.0 / 25	lower is better
Support and ecosystem	16.5 / 20	higher is better
AI leverage	2.0 / 20	higher is better
Ledger Index	66.2 / 100	balanced weights

Capability by domain

Scores 0 to 5 against fixed anchors; total is weighted to 100.

Domain (weight)	2016	2019	2022	Today
Virtual and physical servers (12)	n/a	n/a	3	3
Databases and applications (12)	n/a	n/a	1.5	1.5
Recovery (14)	n/a	n/a	4	4
Cyber resilience (14)	n/a	n/a	3.5	3.5
Storage efficiency and targets (10)	n/a	n/a	3	4
Long-term retention and tape (6)	n/a	n/a	4	4.5
Replication and DR (10)	n/a	n/a	4	4
Security and compliance (8)	n/a	n/a	4	4.5
New-platform support (VMware exit) (8)	n/a	n/a	3	3
Management at scale and automation (6)	n/a	n/a	4	4.5
Total / 100	not released	not released	66.6	70.6

Year by year: 2020: 55.6 · 2021: 65.2 · 2022: 66.6 · 2023: 68.0 · 2024: 68.0 · 2025: 68.6 · 2026: 70.6

What moved the score

Year	Domain	Change	Points	Trigger
2021	Recovery	3 → 4	+2.8	Live-restore: VM boots while data streams back
2021	Replication and DR	3.5 → 4	+1.0	2.1: bandwidth control
2021	Storage efficiency and targets	2.5 → 3	+1.0	1.1: LTO tape backup
2022	Cyber resilience	3 → 3.5	+1.4	Protected snapshots; verify schedules
2023	Long-term retention and tape	4 → 4.5	+0.6	2.4: WORM tape
2023	Security and compliance	4 → 4.5	+0.8	2.4: LDAP and Active Directory realms
2025	Management at scale and automation	4 → 4.5	+0.6	Datacenter Manager integration; metrics export
2026	Storage efficiency and targets	3 → 4	+2.0	4.2: S3 object storage fully supported

Direction, 2023 to 2026

Each item carries one theme and one driver (V vision, C customer need, M market window, U upstream, P portfolio).

Date	Item	Theme	Driver
2023-03	2.4: LDAP/AD realms, WORM tape	D9 Security	C
2023-06	3.0: Debian 12 base	D12 Packaging and licensing	U
2024-04	3.2: notification system, VMA importer, backup fleecing	D10 Scale and automation	C
2024-11	3.3: push-based sync	D6 Replication and DR	C
2025-04	3.4: static Linux client	D11 Ecosystem openness	C
2025-08	4.0: Debian 13, S3 preview	D5 Storage efficiency	U
2026-04	4.2: S3 supported, server-side encryption for push sync	D5 Storage efficiency	C
2026-04	4.2: move groups and namespaces, concurrent sync workers	D10 Scale and automation	C

Centre of gravity: Scale and automation (2), Storage efficiency (2), Security (1)
Driver mix: Vision 0%, Customer need 75%, Market window 0%, Upstream 25%, Portfolio 0%

Credibility: 21.0 / 25

Criterion	Score	Basis
Cadence	4.5	Two to three releases a year, aligned with Proxmox VE
Roadmap transparency	4.5	Public roadmap wiki with history, git and Bugzilla
Say-do	4	10 of 10 roadmap items shipped; S3 took 34 months from first listing
Velocity	4	Several substantive features per release
Lifecycle stability	4	Major per Debian release, in-place upgrades

Say-do record, 2023 to 2026: 10 items from the roadmap wiki since 2023, all shipped, mostly within 4 to 12 months; S3 storage took 34 months (preview in 4.0, supported in 4.2).

Sustainability risk: 7.0 / 25 (lower is better)

Criterion	Score	Basis
Maintainer concentration	3.5	Effectively all commits by Proxmox staff
Backer health	1	Profitable, privately held company with a large installed base
Licence-change risk	1.5	AGPLv3; no relicensing history
Abandonment signs	0	Active development and releases
Security response	1	Active maintenance with public bug tracker

Project health: Last release 2026-04-29. Development by Proxmox Server Solutions staff; repository on git.proxmox.com, bugs on Bugzilla. 2 to 3 releases a year since 2020.

Technical lock-in: 7.0 / 25 (lower is better)

Criterion	Score	Basis
Formats	2	Proprietary chunk and index format, readable by the open-source client
Export path	1	Static client restores or mounts backups on any Linux
Stack coupling	2.5	Debian-based server; VM backup tied to Proxmox VE
Hardware / cloud coupling	0	Any x86 server; offline mirror for air gaps
Skills and tooling coupling	1.5	Proxmox skills

Support and ecosystem: 16.5 / 20

Criterion	Score	Basis
Paid support	4.5	Published prices, four tiers, 24/7 from October 2026
Consultants and partners	4	More than 200 listed partners; training
Documentation	4	Full admin guide and built-in API viewer
Community and packaging	4	Very active forum; own Debian repositories

AI leverage: 2 / 20

Strand	Today	Latest step
AI for protection / protecting AI	0	none
AI platform stack	0	none
AI-assisted operations	0	none
Agent openness	2	2020: Full REST API with tokens; MCP servers are community-only

No AI or machine-learning feature, and none on the roadmap.

Reading

PBS is the most polished open-source backup product here, with live-restore, global dedupe, tape and S3, and a public roadmap it delivers on. Its limit is scope: agentless VM backup works only for Proxmox VE, and there are no Windows or database agents. For a Proxmox estate it is the natural choice; outside one, it covers Linux file backup only.

Open questions and evidence caveats

Windows clients and Proxmox VE host backup are roadmap items with no date.
Third-party vendors (Veeam, NAKIVO) now back up Proxmox through its backup-provider API, which competes with PBS.