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Backup · head to head

Duplicacy vs Proxmox Backup Server

Duplicacy logo

Duplicacy

Backup

Lock-free deduplication cloud backup

From
Free
Rated
-
Full reviewWebsite
Proxmox Backup Server logo

Proxmox Backup Server

Backup

Deduplicating backup server for virtual machines, containers and Linux hosts, with verification built in

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Duplicacy web GUI pricing tier not specified on product page; Proxmox Backup Server there is no Windows client, so physical Windows machines must be backed up by something else and the estate ends up with two backup products.
  • They diverge on capability: Duplicacy covers Lock-free deduplication, Proxmox Backup Server covers Deduplicated chunk store.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Duplicacy and Proxmox Backup Server actually diverge.

Attributes where Duplicacy and Proxmox Backup Server differ
AttributeDuplicacyProxmox Backup Server
Pricing modelfreemiumOpen source, no licence fee
PlatformsmacOS, Linux, WindowsLinux
Founded2016Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Backup).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Duplicacy

  • Lock-free deduplication
  • Client-side encryption
  • Multiple computers
  • Erasure coding
  • Variable-size chunking
  • RSA encryption
  • AWS S3
  • Azure

Only in Proxmox Backup Server

  • Deduplicated chunk store
  • Incremental guest backups
  • Client side encryption
  • Verification jobs
  • Remote sync
  • Live restore and file level restore

What people use each for

The jobs each tool is most often brought in to do.

Duplicacy

  • Client-side encrypted cloud backupsnot Proxmox Backup Server
  • Lock-free deduplication for efficient backup storagenot Proxmox Backup Server
  • Multi-destination backup supportnot Proxmox Backup Server

Proxmox Backup Server

  • Backing up a Proxmox VE cluster with incremental block level backups of running guestsnot Duplicacy
  • Replacing a backup product whose licence is priced per socket or per terabyte on a virtualisation estatenot Duplicacy
  • Proving backup integrity on a schedule rather than discovering corruption during a restorenot Duplicacy
  • Keeping an encrypted second copy on a remote server or on tape without a third party servicenot Duplicacy

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Duplicacy

  • Web GUI pricing tier not specified on product page

Proxmox Backup Server

  • There is no Windows client, so physical Windows machines must be backed up by something else and the estate ends up with two backup products.
  • The datastore is millions of small chunk files, so it needs storage with real input and output capability and performs poorly on a single spinning disk or an SMB or NFS share.
  • Deduplication is per datastore, so splitting workloads across datastores for retention or tenancy reasons multiplies the storage those workloads consume.
  • Garbage collection depends on file access time semantics on the underlying filesystem, so a datastore mounted with the wrong options can fail to reclaim space or, worse, behave unpredictably.
  • Subscriptions are priced per CPU socket per year, so a backup server consolidated onto fewer larger dual socket machines pays twice per host for the supported repository.

Pricing, plan by plan

Duplicacy

Free

No published plan breakdown. See the Duplicacy review.

Proxmox Backup Server

Free
  • No subscriptionFree
    • Full functionality with no capacity limit
    • Community package repository
    • Community forum support
  • Subscription$undefined/year
    • Priced per CPU socket per year
    • Access to the enterprise package repository
    • Vendor support tickets

Which should you pick?

Choose Duplicacy if

  • You need lock-free deduplication.
  • You want to start without paying.
  • You work on macOS, Linux, Windows.
  • You also want client-side encryption.
Duplicacy review

Choose Proxmox Backup Server if

  • You need deduplicated chunk store.
  • You want to start without paying.
  • You work on Linux.
  • You also want incremental guest backups.
Proxmox Backup Server review

Questions people ask

Is Duplicacy or Proxmox Backup Server better?
Neither clearly leads. Duplicacy starts at Free and Proxmox Backup Server at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Duplicacy or Proxmox Backup Server?
Duplicacy starts at Free and Proxmox Backup Server at Free.
Does Duplicacy or Proxmox Backup Server run on more platforms?
Duplicacy runs on macOS, Linux, Windows. Proxmox Backup Server runs on Linux.
Can I use Duplicacy for free?
Both have a free tier, so you can try either at no cost before committing.
What is Duplicacy best used for?
Duplicacy is most often used for client-side encrypted cloud backups, lock-free deduplication for efficient backup storage, multi-destination backup support. Of those, client-side encrypted cloud backups and lock-free deduplication for efficient backup storage are not what Proxmox Backup Server is typically brought in for.
What can Duplicacy do that Proxmox Backup Server cannot?
Duplicacy covers Lock-free deduplication, Client-side encryption, Multiple computers, Erasure coding. Proxmox Backup Server covers Deduplicated chunk store, Incremental guest backups, Client side encryption, Verification jobs.

Answered from the vendors’ own pages

Duplicacy: What is the cost of the Duplicacy command line version for commercial use?

The commercial license for Duplicacy's command line version costs $50 per machine per year. The CLI version is free for individual users.

Source
Proxmox Backup Server: Can it back up machines that are not on Proxmox?

Linux hosts yes, through the client, at file level. Other hypervisors and physical Windows machines are outside its scope.

Duplicacy: Is pricing available for the Duplicacy Web GUI edition?

No pricing information is provided for the Web Edition (GUI) on the Duplicacy website. You would need to contact [email protected] for Web Edition pricing details.

Source
Proxmox Backup Server: Is a subscription required?

No. Without one you use the community repository and forum support. The subscription buys the tested enterprise repository and vendor tickets.

Duplicacy: Are volume discounts available for IT service providers?

Yes, volume discounts are available for IT service providers and resellers. Contact [email protected] to discuss volume pricing options.

Source
Proxmox Backup Server: How do I know a backup will restore?

Run verification jobs. They re-read the stored chunks and mark snapshots verified or failed, which is stronger evidence than a successful backup log.

Duplicacy: What backup modes and features are included in the free version?

The free version includes file, disk, partition, and system backup with full, incremental, and differential backup modes. It also offers scheduled backups, encryption, and emergency disk creation.

Source
Proxmox Backup Server: What storage should the datastore be on?

Local disks, ideally with ZFS and enough input and output capacity for many small files. Network shares are supported but routinely disappointing.

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