Thanos vs Mimir – Choosing the Right Prometheus Extension

Grafana
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Introduction: Breaking Prometheus’ limits

Prometheus alone cannot meet enterprise demands for high availability, long-term retention, disaster recovery, and multi-cluster observability. This gap has led to several extension projects — Thanos, Cortex, Mimir, and VictoriaMetrics.

Project comparison snapshot

Comparison Prometheus federation Thanos Grafana Mimir VictoriaMetrics Cortex
High availability :cross_mark: :white_check_mark: :white_check_mark: :white_check_mark: :white_check_mark:
Remote storage :cross_mark: :white_check_mark: :white_check_mark: :cross_mark: :cross_mark:
Aggregated view :white_check_mark: :white_check_mark: :white_check_mark: :white_check_mark: :white_check_mark:
Documentation Limited Good Limited Excellent Excellent
Maturity Mature Mature Early stage Mature Mature

Among these, Thanos and Mimir are the most widely adopted and debated. Let’s compare them in detail.

Thanos: simplicity and reliability

Thanos enhances Prometheus with a sidecar model:

  • Sidecar: Uploads local blocks to object storage
  • Query: Aggregates results from multiple sources
  • Store Gateway: Serves block data from object storage
  • Compactor: Downsamples and compacts TSDB blocks
  • Ruler: Evaluates alert and recording rules

Advantages:

  • Easy to set up
  • Well-documented
  • CNCF Incubating with strong community

Mimir: scalability at Grafana scale

Mimir is designed for extreme scalability and forms the metrics backbone of the LGTM stack.

  • Ingester / Distributor / Querier pipeline
  • RemoteWrite-based ingestion from Prometheus
  • Store Gateway for long-term storage access
  • Compactor and Ruler components

Key strength: consistent query performance at massive scale.

Latency benchmark results

Mimir

Thanos

Mimir maintains low latency even for week-long queries, while Thanos degrades significantly.

Operational trade-offs

Aspect Mimir Thanos
Philosophy Built for scalability & performance Simplicity & cost-efficiency
Architecture RemoteWrite ingestion Sidecar model
Risks Ingester memory pressure Compaction failures
Ecosystem Grafana Labs backed CNCF community
Latency Consistently low High for long queries

Conclusion

  • Mimir is ideal for organizations with rapidly growing metrics and a need for predictable query performance.
  • Thanos remains an excellent choice for teams prioritizing simplicity and strong community backing.

When choosing between Thanos and Mimir, what do you value most?

  • Query performance?
  • Operational simplicity?
  • Ecosystem maturity?
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What do O and X mean? In the US world, these are actually ambiguous.
(Tip, if you want to be crystal clear, use :white_check_mark: and :cross_mark:)

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I see your point. Thanks for the suggestion.

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