Grafana Mimir provides horizontally scalable, highly available, multi-tenant, long-term storage for Prometheus.
C-Rank Grade: S (Elite) - 71/100
External PR Merge Rate: 78%
Response Time: 3d
First Timer Success: 65%
grafana/mimir has a recorded first-timer success rate of 65.4%. Repositories ranked S typically provide actionable feedback during code reviews and actively nurture new community contributors.
Maintainers in grafana/mimir respond to incoming external pull requests in approximately 73.7 hours on average. Keeping PRs focused on single tasks and ensuring tests pass helps maintainers review faster.
The C-Rank™ system evaluates GitHub projects on a 0–100 scale using real data: PR merge rates, review turnaround time, active maintainer presence, and first-time contributor success. A score of 70.5 places grafana/mimir in the S tier.
The external contributor pull request merge rate for grafana/mimir is 78.0%, based on public PR activity from non-core contributors.
grafana/mimir currently has 6 active issue(s) tagged with beginner-friendly labels like "good first issue", "beginner", or "up-for-grabs".
Balanced & professional review environment in grafana/mimir. Maintains strict focus on technical quality and test standards.
Average Response Latency
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External Acceptance Rate
Percentage of community pull requests successfully merged into main.
First PR Conversion
Rate at which developers submitting their first repository PR succeed.
Show contributors that your repository actively reviews and merges external pull requests.
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Historical health & responsiveness evolution
External PR acceptance
First PR success rate
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Maintainer review activity heatmap & prime window prediction
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Maintainers are most responsive around 14:00 UTC (14:00 UTC in your timezone). Recommended submission window is Wednesday - Friday from 12:00 to 16:00 UTC (12:00 - 16:00 UTC local).
Maintainer Strategy: Maintainer Sweet Spot: PRs under 150 lines merge in ~48 hours (96% approval). Large PRs (>500 lines) take ~354 hours (35% approval). Keep your diff compact for rapid review.
What is the bug? The official Grafana documentation located at: https://grafana.com/docs/mimir/latest/configure/configure-kafka-backend/ states that Kafka should be configured with: KAFKA_MESSAGE_MAX_BYTES = 16000000 (maybe better to use: 16777216) At the same time, the Mimir helm chart does not set this value anywhere. How to reproduce it? Deploy a Mimir large setup in production and see the following errors: not retryable error: Permanent error: rpc error: code = InvalidArgument desc = error exporting items, request to https://mimir-gateway.mimir.svc.cluster.local/otlp/v1/metrics responded with HTTP Status Code 400, Message=send data to partitions: failed pushing to partitions: the write request contains a timeseries or metadata item which is larger that the maximum allowed size of 15983616 bytes (err-mimir-distributor-max-write-request-data-item-size What did you think would happen? Mimir should run without issues when deployed with the official helm chart. The helm chart should fol
What is the bug? Some kafkatool commands require the user to pass the --kafka-address, but do not contact a remote server at all. This is inconvenient and confusing. I don't have an exhaustive list of commands. I believe the flag is required for all commands, so we should just look for all commands that don't use it. Here are some: dump analyse dump print dump find-duplicates How to reproduce it? $ ./kafkatool dump --file ./dump.json analyse kafkatool: error: required flag(s) '--kafka-address' not provided, try --help What did you think would happen? We should not require the --kafka-address flag when it's not required. What was your environment? n/a Any additional context to share? No response
What is the problem you are trying to solve? Hi Grafana-Labs We're working on upgrading to Ingest-Storage using MSK as our Kafka backend and we're testing IAM auth introduced in 3.1 but it doesn't support IRSA auth similar to block-storage S3. For block-storage we simply don't set static-credentials and Mimir uses the IAM role of the service account associated with the Pod, but this doesn't work for Kafka as we hit the following validation error: https://github.com/grafana/mimir/blob/main/pkg/storage/ingest/config.go#L40 We can work around this by creating a socket to get the credentials but ideally we could just rely on IRSA auth of the Service Account. Which solution do you envision (roughly)? Kafka code path can handle auth to AWS MSK clusters in a similar manner to how it handles AWS S3 auth, that when no config fields are set it tries to use IRSA auth for the Pods Service Account. Have you considered any alternatives? No response Any additional context to share? No response How lo
What is the bug? After upgrading from mimir-distributed-5.8.0 to mimir-distributed-6.0.5, the Ingress for alertmanager paths breaks with: <error: services "mimir-alertmanager" not found> This affects all alertmanager ingress paths: /alertmanager /multitenant_alertmanager/status /multitenant_alertmanager/configs /api/v1/alerts Root Cause PR #13064 introduced this breaking change in 6.0.0: [CHANGE] Ingress: Change default routes to point to non-headless services. #13064 The ingress template was changed to use mimir-alertmanager (ClusterIP) instead of mimir-alertmanager-headless. However, when alertmanager.zoneAwareReplication.enabled=true, the chart never creates a mimir-alertmanager ClusterIP service — only zone-specific services and the headless service are created. Services that exist with zoneAwareReplication enabled: mimir-alertmanager-headless ClusterIP None 8080/TCP mimir-alertmanager-zone-a ClusterIP <IP> 8080/TCP mimir-alertmanager-zone-b ClusterIP
What is the problem you are trying to solve? When running a big instance of mimir v3 we found ourselves with throughput of 0.5GB per second (2000000 active series) Which solution do you envision (roughly)? Can it be possible to enable by flag the option to push and pull compressed data into the kafka between the distributor and the ingestor? Have you considered any alternatives? No response Any additional context to share? No response How long do you think this would take to be developed? Small (<= 1 month dev) What are the documentation dependencies? Feature Flags Proposer? No response
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When evaluating whether to contribute to grafana/mimir, response velocity and maintainer engagement are crucial. GetMerged continuously tracks pull request trajectories, first-comment latency, and code review rounds to help developers avoid submitting pull requests to backlogged repositories.
Currently, maintainers of grafana/mimir acknowledge new external contributions in approximately 3 days+. Out of all submitted pull requests from non-core authors in the last 180-day window, 78.0% were successfully merged into the primary branch.
grafana/mimir has a recorded first-timer success rate of 65.4%. Repositories ranked Elite typically provide actionable feedback during code reviews and actively nurture new community contributors.
The initial maintainer response time averages ~3 days+. Keeping PRs scoped to single concerns and ensuring CI checks succeed will optimize review turnaround.
The C-Rank™ index scores repositories on a 0 to 100 scale using an objective formula: external PR merge rates, initial response speed, active maintainer count, and first-time contributor retention. A score of 70.5 places grafana/mimir in the Elite tier.
The external pull request merge rate is 78.0%. GetMerged isolates non-core community contributions so external developers get an accurate benchmark of PR acceptance probability.
Yes, grafana/mimir currently has 6 active issue(s) tagged with beginner-friendly labels. You can inspect these directly from the repository issues tab.
All metrics displayed for grafana/mimir are automatically retrieved via the public GitHub API and recalculated daily. Insider pull requests submitted by repository owners or organization members are excluded from merge rate calculations to preserve objective external contributor statistics.