Atlas: tune alerts so real problems page and noise does not

Alert tuning

Symptom: alert fatigue (ignored pages) or silent incidents (no alert fired).

Diagnose

List current alert configs (Atlas UI, Alerts, Alert Settings). For each firing alert ask: did a human need to act? For each recent incident ask: did any alert fire?

Confirm

Check the metric baseline first. A connections alert at a fixed number is meaningless without knowing your normal peak. Pull a week of the metric and set thresholds relative to it.

Fix

• Thresholds from baseline: e.g. connections above 80% of tier cap sustained 5 minutes, disk above 75%, replication lag above your SLA.
• Route by severity: page for data-loss risks (replication, backup failures), notify chat for early warnings (disk 75%, slow query uptick).
• Maintenance windows during deploys and index builds so planned work does not page.
• Every alert needs a runbook link: what to check first. An alert nobody knows how to answer is noise.

Verify

Run a controlled trigger (a staging load test that crosses a threshold) and confirm the right channel fires with the runbook attached. Review quarterly.

Atlas alert configuration (conditions, thresholds, notifications, maintenance windows) per https://www.mongodb.com/docs/atlas/alerts/, verified 2026-09-26.