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File Storage · head to head

Ceph vs Thanos

Ceph logo

Ceph

File Storage

Open source distributed storage providing object, block and file from one cluster

From
Free
Rated
-
Full reviewWebsite
Thanos logo

Thanos

Cloud

Highly available Prometheus with long-term object storage

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Ceph ceph assumes an operator who understands placement groups, CRUSH rules and recovery tuning, so organisations without dedicated storage staff routinely end up with a cluster that works until the first failure and then does not.; Thanos several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • They diverge on capability: Ceph covers RADOS object store, Thanos covers Global query.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Ceph and Thanos actually diverge.

Attributes where Ceph and Thanos differ
AttributeCephThanos
PlatformsLinuxKubernetes, Linux, Docker
CategoryFile StorageCloud

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated).

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 Ceph

  • RADOS object store
  • RADOS Gateway
  • RBD block devices
  • CephFS
  • CRUSH placement
  • Erasure coded pools

Only in Thanos

  • Global query
  • Object storage retention
  • Deduplication
  • Downsampling

What people use each for

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

Ceph

  • Backing a private cloud where virtual machine disks, shared filesystems and an S3 endpoint all need the same hardwarenot Thanos
  • Growing past the point where a proprietary array upgrade costs more than a rack of commodity serversnot Thanos
  • Research and media environments with petabytes of data and staff who can operate storagenot Thanos
  • Providing an S3 endpoint on premises with multi site replication under your own controlnot Thanos

Thanos

  • Querying metrics across many clusters or regions from one placenot Ceph
  • Retaining metrics for years without local disk growthnot Ceph
  • Removing the gap that appears when a single Prometheus instance restartsnot Ceph

Where each one falls short

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

Ceph

  • Ceph assumes an operator who understands placement groups, CRUSH rules and recovery tuning, so organisations without dedicated storage staff routinely end up with a cluster that works until the first failure and then does not.
  • Small clusters are inefficient: three way replication means a third of raw capacity is usable, and erasure coding needs enough failure domains to be safe, so the economics only work above a certain size.
  • Recovery and rebalancing generate heavy internal traffic, so a failed disk can degrade client latency across the cluster unless backfill is throttled correctly beforehand.
  • Upgrades must follow a strict daemon order across monitors, managers, OSDs and gateways, and a mistake in that order on a live cluster is difficult to reverse.
  • Because it is self hosted, every byte served to the internet is transit you pay for on your own links, so the free licence does not mean free egress and bandwidth planning becomes your problem rather than the providers.

Thanos

  • Several components — sidecar, store, querier, compactor, ruler — each with its own configuration and failure modes
  • The compactor is a common source of operational trouble and must not run twice against the same bucket
  • Query latency over object storage is meaningfully higher than local Prometheus
  • Object storage costs and API request charges become real at high volume

Pricing, plan by plan

Ceph

Free
  • CephFree
    • Full functionality, no capacity limit
    • Object, block and file interfaces
    • Community support via mailing list and Slack

Thanos

Free
  • ThanosFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Ceph if

  • You need rados object store.
  • You want to start without paying.
  • You work on Linux.
  • You also want rados gateway.
Ceph review

Choose Thanos if

  • You need global query.
  • You want to start without paying.
  • You work on Kubernetes, Linux, Docker.
  • You also want object storage retention.
Thanos review

Questions people ask

Is Ceph or Thanos better?
Neither clearly leads. Ceph starts at Free and Thanos at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Ceph or Thanos?
Ceph starts at Free and Thanos at Free.
Does Ceph or Thanos run on more platforms?
Ceph runs on Linux. Thanos runs on Kubernetes, Linux, Docker.
Can I use Ceph for free?
Both have a free tier, so you can try either at no cost before committing.
What is Ceph best used for?
Ceph is most often used for backing a private cloud where virtual machine disks, shared filesystems and an s3 endpoint all need the same hardware, growing past the point where a proprietary array upgrade costs more than a rack of commodity servers, research and media environments with petabytes of data and staff who can operate storage, providing an s3 endpoint on premises with multi site replication under your own control. Of those, backing a private cloud where virtual machine disks, shared filesystems and an s3 endpoint all need the same hardware and growing past the point where a proprietary array upgrade costs more than a rack of commodity servers are not what Thanos is typically brought in for.
What can Ceph do that Thanos cannot?
Ceph covers RADOS object store, RADOS Gateway, RBD block devices, CephFS. Thanos covers Global query, Object storage retention, Deduplication, Downsampling.

Answered from the vendors’ own pages

Ceph: How many nodes do I need to start?

Three is the practical minimum for a replicated cluster with real fault tolerance, and most production advice starts at five once you account for maintenance windows.

Thanos: Is Thanos free?

Yes, open source and CNCF-incubating. Costs are the object storage it uses.

Ceph: Is it faster than a SAN?

Not on single stream latency. It wins on aggregate throughput and on growing without a forklift upgrade, which is a different property from raw speed.

Thanos: Does Thanos replace Prometheus?

No. It runs alongside existing Prometheus servers, adding global query, deduplication and long-term storage.

Ceph: Can I buy support?

Yes. IBM sells IBM Storage Ceph and SUSE and others have offered supported builds; the upstream project itself is free.

Thanos: Thanos or VictoriaMetrics?

Thanos layers onto Prometheus using object storage and is the more established multi-cluster answer. VictoriaMetrics is a separate store aiming at lower resource use and fewer moving parts.

Ceph: Should I use it just for S3?

If object is all you need, a dedicated object store is simpler to run. Ceph earns its complexity when you need block and file as well.

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