Loki + Tempo + Mimir

Loki + Tempo + Mimir

This is Grafana Labs' open-source observability stack, designed for scale and cost efficiency by storing logs, traces, and metrics in inexpensive object storage. Loki handles logs, Tempo handles traces, and Mimir provides long-term, horizontally scalable Prometheus-compatible metrics. Grafana is the unified front end across all three.

The stack targets organizations that want the open-source Grafana ecosystem at large scale, with cheap storage and a single pane of glass, typically running on Kubernetes.

Components

• Loki aggregates logs and indexes only labels rather than full text, keeping storage cheap and queries efficient via LogQL.
• Tempo stores distributed traces cost-effectively in object storage, retrieving by trace ID and integrating with metrics and logs.
• Mimir provides scalable, highly available long-term storage for Prometheus metrics, accepting remote-write from Prometheus.
• Object storage such as Amazon S3 backs all three for cheap, durable retention.
• Grafana unifies dashboards and enables correlation across logs, traces, and metrics.
• Kubernetes is the common deployment substrate.

Strengths

Using object storage for all three signals makes long retention affordable at scale. The three components share design philosophy and integrate tightly in Grafana, enabling fast pivots from a metric spike to related traces and logs. Loki's label-only indexing keeps log costs low. Mimir scales Prometheus metrics horizontally with high availability. Everything is open source and self-hostable, avoiding SaaS per-host fees, and PromQL, LogQL, and TraceQL share a coherent query experience.

Trade-offs

The stack is operationally complex: each component is a distributed system to deploy, scale, and tune. Object-storage query latency requires caching for good performance. Loki's label-only indexing means high-cardinality or ad hoc full-text searches can be slow if labels are poorly designed. Running all three well needs strong platform engineering. For small environments, a single Prometheus plus simpler logging is far easier.

When to Use It

Choose Loki + Tempo + Mimir when you are committed to the open-source Grafana ecosystem, need logs, traces, and metrics at scale with affordable long-term retention, and have platform engineering capacity to operate distributed systems. For small setups or teams preferring a managed service, simpler open-source tools or Grafana Cloud reduce operational load.