Grafana Mimir: Long-Term Metrics Storage at Scale

Written By:
Founder & CTO
June 24, 2025

In the evolving landscape of cloud-native observability and performance monitoring, Grafana Mimir has emerged as a robust, high-performance backend for long-term metrics storage at massive scale. Designed with scalability, resilience, and developer flexibility in mind, Grafana Mimir addresses many of the limitations faced by traditional time-series databases like Prometheus. Whether you're managing observability data for a Kubernetes environment, microservices architecture, or distributed infrastructure, this blog post will walk you through the why, how, and what of using Grafana Mimir, through the lens of a developer.

We’ll explore how Mimir works, its benefits, architecture, deployment options, and its compelling advantages over traditional tools. This isn’t just a feature list, this is a deep dive written for developers who want full control over their metrics retention, query performance, cost, and observability stack.

What is Grafana Mimir?

Grafana Mimir is an open-source, horizontally scalable, multi-tenant time-series database designed to offer durable, long-term metrics storage. Developed by Grafana Labs as the next step in the evolution of Cortex, Mimir enhances Prometheus compatibility while enabling developers to ingest, store, and query billions of active time series efficiently.

Whereas Prometheus has limits on high availability, persistent storage, and scaling, Grafana Mimir delivers a resilient metrics platform that supports Prometheus remote write, PromQL queries, multi-tenancy, and backend durability using object storage systems like AWS S3, Google Cloud Storage, or Azure Blob Storage. For developers running production workloads in modern distributed systems, this ensures observability data is no longer ephemeral.

Why Developers Should Care About Grafana Mimir

For developers building and maintaining cloud-native systems, observability isn’t a luxury, it’s a necessity. Modern applications are broken into microservices, often deployed using container orchestration platforms like Kubernetes. Each of these services emits logs, metrics, and traces. Among them, metrics, quantitative measurements of system performance, are essential for alerting, autoscaling, and historical analysis.

Traditional setups using Prometheus alone often hit a ceiling:

  • Data is lost on crash unless snapshots are exported manually.

  • Retention is short due to local disk limitations.

  • HA is tricky, requiring manual sharding or federation.

  • Querying across services is brittle or slow at scale.

Grafana Mimir solves these issues. It stores metrics long-term in cloud object storage, supports horizontal scalability out of the box, and enables multi-tenant setups for team-based or customer-isolated environments.

This makes Grafana Mimir ideal for SaaS platforms, infrastructure teams, SREs, DevOps engineers, and observability architects.

Key Developer Benefits of Grafana Mimir

Let’s break down the core benefits of Grafana Mimir, with developer-centric explanations and secondary keyword optimization.

100% Prometheus-Compatible API

Grafana Mimir is fully compatible with Prometheus’s remote write and PromQL query APIs. This means you don’t need to change your existing Prometheus agents or exporters. You can continue using node_exporter, kube-state-metrics, cAdvisor, or any of your custom metrics exporters without rewriting a single line.

This API-level compatibility ensures Grafana Mimir can be dropped into your stack as a backend for long-term metrics storage, with minimal reconfiguration. It supports existing alert rules, recording rules, Grafana dashboards, and integrations.

This compatibility is critical for teams who have invested heavily in the Prometheus ecosystem but have grown out of its storage and scaling limitations.

Unlimited Horizontal Scalability for High-Volume Metrics

Grafana Mimir is horizontally scalable by design. Its architecture is composed of independently deployable microservices, each of which can be scaled independently based on the component's function (ingester, querier, compactor, etc.).

This modularity enables Mimir to handle billions of active time series with consistent ingestion and query performance. Ingestion, compaction, and querying can be scaled out by adding more replicas, enabling developers to build observability platforms that scale with their infrastructure.

If your team is monitoring:

  • Thousands of pods across Kubernetes clusters

  • Global IoT devices

  • High-frequency telemetry from financial or gaming platforms

Grafana Mimir ensures that your metrics ingestion pipeline never becomes the bottleneck.

High Availability and Replication

Grafana Mimir supports high availability through redundant ingestion streams and state replication. It uses a write-ahead log to buffer metrics temporarily and supports replicated ingestion to avoid data loss in case of node failures.

For developers, this means zero-downtime observability during failovers or upgrades. Metrics that are ingested are safely replicated and flushed to object storage, ensuring durable observability history even in dynamic, multi-zone environments.

This resilience is especially beneficial for production environments where uptime is critical and metrics are often used for autoscaling, circuit breaking, or anomaly detection.

Long-Term Durable Storage in the Cloud

One of Mimir’s most significant strengths is its native integration with object storage. Metrics are flushed from memory to blocks, compacted, and stored in services like Amazon S3, Google Cloud Storage, Azure Blob, or MinIO. This allows developers to store months or even years of high-resolution metrics affordably.

Object storage provides durability, scalability, and cost-efficiency, eliminating the need for complex cold storage or roll-up strategies.

With Grafana Mimir:

  • You can configure per-tenant retention policies.

  • You can query historical metrics from up to multiple years ago.

  • You get deduplication and compaction out of the box.

For developers, this means reliable historic trends, precise capacity planning, and forensics over time, all backed by cheap and durable cloud storage.

Multi-Tenancy with Organizational Isolation

Grafana Mimir was built with multi-tenancy at its core. It supports per-tenant ingestion, querying, and storage quotas. This is essential for:

  • SaaS providers offering monitoring to different customers

  • Platform teams offering observability as a service internally

  • Enterprise use cases with business-unit-level data separation

Each tenant can be identified using a unique header (e.g., X-Scope-OrgID), and you can control how much storage, compute, or query bandwidth they use.

This makes it a developer-friendly solution for building secure, isolated, and efficient observability platforms without setting up multiple clusters.

Core Components and Architecture

Grafana Mimir’s architecture is composed of several key components, each responsible for a part of the ingestion-storage-query pipeline:

Distributor

The distributor receives metrics from Prometheus remote write or Grafana Agent and routes them to appropriate ingester nodes. It performs sharding based on series fingerprints to ensure balanced load distribution.

Ingester

Ingesters hold metrics in memory temporarily and flush them to block storage periodically. They support replicated ingestion and are stateless between restarts.

Compactor

The compactor merges multiple TSDB blocks from ingesters into larger, optimized blocks. It also deduplicates overlapping data and enforces retention settings.

Store-Gateway

The store-gateway fetches blocks from cloud storage and serves them to queriers. It ensures historical data is queryable with low latency and high availability.

Querier and Query Frontend

The querier executes PromQL queries across both recent and historical data. The query frontend handles caching, sharding, and query scheduling to optimize performance and reduce load.

Alerting and Rules

Mimir includes a ruler component that executes Prometheus recording and alerting rules. It supports multi-tenant rules and long-term alert history, improving the observability feedback loop.

This component-based design makes Mimir a developer-optimized, cloud-native system that’s easy to scale and debug.

How to Deploy Grafana Mimir
Monolithic Mode

For testing or local development, Grafana Mimir can run in monolithic mode using a single binary. This is useful for prototyping or running on local clusters without complex Helm or Kubernetes setups.

Run it with proper configuration flags pointing to local or test object storage, and begin ingesting data with Prometheus or Grafana Agent.

Kubernetes Helm-Based Deployment

In production, Grafana Mimir is best deployed using the official Helm chart. This provides out-of-the-box scalability and cloud storage integration.

Steps:

  1. Add Grafana Helm repo and update.

  2. Create S3-compatible buckets for blocks, rules, and alerts.

  3. Customize values.yaml for tenant limits, object storage, and replicas.

  4. Enable compactor and query frontend sharding.

  5. Use Horizontal Pod Autoscalers for distributor and querier components.

  6. Secure endpoints with mTLS or basic auth for enterprise deployments.

Once deployed, connect Mimir to Grafana OSS or Grafana Cloud via the Prometheus datasource panel using the remote read/write endpoints.

Scaling and Best Practices
  • Start small and scale out each component individually.

  • Use object storage with versioning and lifecycle policies to manage costs.

  • Monitor compactor and store-gateway performance closely.

  • Enable caching in query frontend to reduce cold queries.

  • Rotate ingesters gracefully to avoid data loss.
Advantages Over Traditional Time-Series Storage

Grafana Mimir offers several advantages compared to alternatives:

  • Versus Prometheus: Mimir supports high availability, remote storage, and multi-tenancy, which Prometheus lacks.

  • Versus Thanos: Mimir offers better query performance with sharded frontend and more simplified configuration.

  • Versus Cortex: Mimir is a cleaner, more maintainable fork of Cortex with improved architecture, docs, and operational patterns.

If you're currently maintaining a fleet of Prometheus instances with federation or looking for alternatives to hosted observability platforms, Mimir is the self-hosted, cloud-native solution to bet on.

Developer Use Case Narratives

Imagine you're part of a team responsible for a real-time analytics platform. Every microservice emits metrics, and you have 1 million active time series. Prometheus begins to struggle. You:

  • Deploy Mimir on Kubernetes with Helm.

  • Route all metrics via Grafana Agent to Mimir’s distributor.

  • Enable recording rules for aggregate metrics.

  • Store all data in AWS S3 with 2-year retention.

  • Use Grafana dashboards to monitor performance across time.

Within days, your team can observe historical trends, compare performance week-over-week, and avoid outages, without touching your Prometheus configuration.

Final Thoughts

Grafana Mimir delivers on the promise of long-term metrics storage at scale. Built with the developer in mind, it offers unmatched compatibility with Prometheus, horizontal scalability, durable object storage, and multi-tenant flexibility, all with an architecture that grows as your infrastructure grows.

Whether you’re running 100 pods or 100,000, Grafana Mimir ensures your metrics are scalable, queryable, and durable, giving developers peace of mind and operational visibility.