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Backup · head to head

Datto SIRIS vs Proxmox Backup Server

Datto SIRIS logo

Datto SIRIS

Backup

All-in-one business continuity and disaster recovery

From
$1095/one-time + recurring
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

  • Only Proxmox Backup Server has a free tier, so it costs nothing to try first.
  • Each has a real cost: Datto SIRIS requires on-premises appliance, not purely cloud-native; 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: Datto SIRIS covers Instant virtualization, 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 Datto SIRIS and Proxmox Backup Server actually diverge.

Attributes where Datto SIRIS and Proxmox Backup Server differ
AttributeDatto SIRISProxmox Backup Server
Starting price$1095/one-time + recurringFree
Pricing modelUnknownOpen source, no licence fee
Free tierNoYes
PlatformsLinux, Virtual EnvironmentsLinux
Founded2011Unknown

Identical on both: 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 Datto SIRIS

  • Instant virtualization
  • Screenshot verification
  • Ransomware detection
  • Inverse chain technology
  • Cloud-first architecture
  • Automated DR testing
  • VMware
  • Hyper-V

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.

Datto SIRIS

  • Data protectionnot Proxmox Backup Server
  • Disaster recoverynot Proxmox Backup Server
  • Business continuitynot Proxmox Backup Server
  • Ransomware protectionnot Proxmox Backup Server
  • Compliancenot Proxmox Backup Server

Proxmox Backup Server

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

Where each one falls short

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

Datto SIRIS

  • Requires on-premises appliance, not purely cloud-native
  • Initial setup and hardware costs can be substantial for smaller MSPs

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

Datto SIRIS

$1095/one-time + recurring

No published plan breakdown. See the Datto SIRIS 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 Datto SIRIS if

  • You need instant virtualization.
  • You work on Linux, Virtual Environments.
  • You also want screenshot verification.
Datto SIRIS 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 Datto SIRIS or Proxmox Backup Server better?
Neither clearly leads. Datto SIRIS starts at $1095/one-time + recurring and Proxmox Backup Server at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Datto SIRIS or Proxmox Backup Server?
Proxmox Backup Server has a free tier; the other does not. Paid plans start at $1095/one-time + recurring for Datto SIRIS and Free for Proxmox Backup Server.
Does Datto SIRIS or Proxmox Backup Server run on more platforms?
Datto SIRIS runs on Linux, Virtual Environments. Proxmox Backup Server runs on Linux.
Can I use Proxmox Backup Server for free?
Yes. Proxmox Backup Server has a free tier, so you can try it without paying. Datto SIRIS starts at $1095/one-time + recurring.
What is Datto SIRIS best used for?
Datto SIRIS is most often used for data protection, disaster recovery, business continuity, ransomware protection. Of those, data protection and disaster recovery are not what Proxmox Backup Server is typically brought in for.
What can Datto SIRIS do that Proxmox Backup Server cannot?
Datto SIRIS covers Instant virtualization, Screenshot verification, Ransomware detection, Inverse chain technology. Proxmox Backup Server covers Deduplicated chunk store, Incremental guest backups, Client side encryption, Verification jobs.

Answered from the vendors’ own pages

Datto SIRIS: What does SIRIS protect against?

Datto SIRIS includes immutable cloud backups, automated recovery verification, and integrated ransomware detection through Cloud Deletion Defense which undoes accidental or malicious backup deletion.

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.

Datto SIRIS: What's the pricing model?

Datto SIRIS uses flat-rate pricing starting at $1,095, which includes installation, storage, VIP support, recoveries, two annual DR tests, and five-year warranty.

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.

Datto SIRIS: What integrations does SIRIS have?

Datto SIRIS integrates natively with Autotask PSA, Datto RMM, ConnectWise Automate, and ConnectWise PSA. It also supports virtualization platforms like vSphere and CentOS Linux.

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.

Datto SIRIS: Is SIRIS cloud-only or appliance-based?

Datto SIRIS is an on-premises appliance that backs up data to Datto's cloud. You do not need to maintain your own physical server infrastructure for the core SIRIS functionality.

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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