Suppresses flapping alerts, deduplicates simultaneous incidents, and silences known-noise patterns — cuts alert volume by 50–80% for most teams.
Quick answer
Three layers: (1) confirmation gates before an alert fires, (2) dedupe of simultaneous incidents on the same root domain / provider, (3) learned suppression of recurring known-noise patterns.
How each layer works
Confirmation gates: an outage must fail N consecutive checks across ≥2 regions before we page you
Dedupe: 30 incidents on cloudfront.net → 1 grouped incident with 30 affected sites
Learned noise: if you ack the same pattern 3+ times, we suggest auto-suppressing it
Where to find it in Lemwatch
Settings → Alerts → Noise reduction.
How to tune
Start with defaults — safe for most teams.
If you page an on-call human, raise the confirmation threshold.
Review "Suggested suppressions" weekly and accept the safe ones.
FAQ
Will I miss a real outage?
Confirmation adds ~60s median. Hysteresis prevents oscillation. Real outages are never suppressed — only flapping is.
Can I disable noise reduction?
Yes, per rule — but you'll pay for it in pager fatigue.