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Monitoring · Advanced · Two weeks with monitoring-pro: what feels right and what drives me up the wall

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MOr/monitoring-pro·posted by swoole_lee·just nowTranslation

Two weeks with monitoring-pro: what feels right and what drives me up the wall

Some background first. Our setup is monitoring-pro plus three downstream services, seven figures of daily requests, peaking around nine in the evening.

Worth noting: the official docs do cover this, just in a very inconspicuous spot. I only found it reading the source comments, where the author explains the reasoning — roughly "so that it degrades into predictable behaviour in extreme cases".

We also fixed monitoring along the way: replaced average-based alerts with percentiles and split them per endpoint. False alerts dropped by about seventy percent and the on-call rotation visibly cheered up.

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13 comments

13 comments

M
Mmike_xuOP·3 minutes ago

Sharing our numbers, 8 cores 16GB, same scenario:

| Concurrency | P50 | P99 |
|---|---|---|
| 200 | 12ms | 88ms |
| 500 | 31ms | 340ms |

P99 clearly collapses at 500 concurrency, which lines up with your knee point.

476
Lli_ming·28 minutes ago

Can you give a minimal reproduction? I ran it locally for ten minutes and could not reproduce on macOS with the latest version.

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LlinlinMod·1 hour ago

I just read the monitoring-pro source — the author actually explains the reasoning in a comment, roughly "so that it degrades into predictable behaviour in extreme cases".

500
RraseOP·1 hour ago

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

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Sslow_query·3 minutes ago

Saved. I am reworking this area this week — this saves a lot of wrong turns.

70
Wwinter·3 minutes ago

Thanks for sharing real numbers — far more useful than the articles that only cover concepts.

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Rran_bo·3 minutes ago

Agreeing with the above. One addition: with this option enabled the GC count in your metrics doubles, so adjust the alert threshold at the same time or it will keep firing.

361
Wwinter·1 hour ago

This matches what we see in production. We only hit it past 3k QPS; the earlier load tests showed nothing — the test traffic was too clean, with no long-tail requests.

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Kkernel_panic·12 minutes ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

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Sslow_query·12 minutes ago

There is actually a simpler fix that needs no architecture change: move this check up to the gateway and the problem disappears. The cost is one extra lookup at the gateway.

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Sslow_query·just now

A question: what changes in a container with a 512Mi memory limit? That is how we run it in production.

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Ddev_zhou·28 minutes ago

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

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Kkite·2 days ago

We have run this in production for two years without hitting it. That said, we never reached this scale, so our experience is not really evidence here.

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