Grafana Loki vs mtail
A side-by-side comparison of two self-hosted monitoring & status options — licensing, setup difficulty, resource needs, and what each one replaces.
Grafana Loki
Log aggregation system inspired by Prometheus
VS
mtail
Extract Prometheus metrics from application log files
| Feature | Grafana Loki | mtail |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 98 · Excellent | 54 · Fair |
| Category | Monitoring & Status | Monitoring & Status |
| License | AGPL-3.0 | Apache-2.0 |
| Language | Go | Go |
| Setup difficulty | Medium | Medium |
| Min. RAM | 512 MB | 64 MB |
| Deployment | docker, kubernetes, helm | docker, binary, kubernetes |
| GitHub stars | ★ 28,937 | ★ 4,032 |
| First released | 2018 | 2015 |
| Replaces | Splunk, Datadog Logs | Splunk, Datadog Log Metrics |
What are Grafana Loki and mtail?
Grafana Loki
Grafana Loki is a horizontally scalable, highly available log aggregation system. Unlike other log systems, it indexes only metadata labels rather than full text, making it cost-effective and simple to operate.
- Label-based log indexing
- LogQL query language
- Tight Grafana integration
- Object storage backend
mtail
mtail is a tool from Google for extracting metrics from application logs to be exported into a time series database. It runs small programs that parse log lines and increment counters or gauges, bridging log data into Prometheus monitoring.
- Turns log lines into metrics
- Compact pattern language
- Prometheus export endpoint
- Low overhead tailing
Grafana Loki vs mtail: key differences
Both projects are written in Go. Licensing differs — AGPL-3.0 for Grafana Loki versus Apache-2.0 for mtail. Mtail is the lighter option, starting around 64 MB of RAM against 512 MB for Grafana Loki. Mtail is the more established project (first released 2015), while Grafana Loki arrived in 2018. Grafana Loki has the considerably larger community, at 28,937 GitHub stars versus 4,032.
Why pick each one
Choose Grafana Loki if…
- Cheap to run compared to full-text indexers
- Familiar Prometheus-style labels
Watch out for
- Limited full-text search
- Requires Grafana for best experience
Choose mtail if…
- Bridges legacy logs to metrics
- Tiny footprint
Watch out for
- Custom program language to learn
- Not a full log pipeline
Frequently asked questions
Is Grafana Loki or mtail better?
Neither is universally better. Grafana Loki has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are Grafana Loki and mtail free and open-source?
Yes. Grafana Loki is licensed under AGPL-3.0 and mtail under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Grafana Loki and mtail with Docker?
Grafana Loki: yes. mtail: yes.
Which is lighter on resources, Grafana Loki or mtail?
mtail has the smaller minimum footprint at 64 MB of RAM, compared to about 512 MB for Grafana Loki. Real-world usage depends on library size, user count, and enabled features.