Mawrooth · RB-MWEMAILRETRY

Email Retry & Bounce Handling — incident runbook

Runbook hubMawrooth console

Email Retry & Bounce Handling is monitored by Retry queue monitor on email retry queue depth. It is owned by Notification Team and serves the business services listed below. Use this runbook when an alert fires on this component.

Warning at email retry queue depth ≥ 25 items, critical at ≥ 80 items. Critical means user-visible impact: page the escalation owner.

dashboard: sim://grafana/mw-email-retrylogs: sim://logs/mw-email-retryowner: Notification Teamrunbook: RB-MWEMAILRETRY

Signals & thresholds

  • Primary metric: email retry queue depth (items)
  • Warning threshold: ≥ 25 items
  • Critical threshold: ≥ 80 items
  • Dashboard: sim://grafana/mw-email-retry
  • Log source: sim://logs/mw-email-retry
  • SLA: 99.5% monthly availability
  • SLO: 99.9% of requests under warning threshold
  • External dependencies: Zoho Mail / ZeptoMail

1. Detection

  1. Retry queue monitor reports email retry queue depth growing past the warning threshold — consumers are not keeping up.
  2. Work items age beyond their expected processing time.

2. Triage

  1. Confirm whether workers are running, crash-looping or blocked on a dependency.
  2. Check sim://logs/mw-email-retry for repeated poison-message failures at the head of the queue.
  3. Compare arrival rate against processing rate to see whether this is an inflow spike or a stalled consumer.

3. Mitigation

  1. Restart or scale out the consumers.
  2. Move poison messages to a dead-letter queue so the backlog can drain.
  3. Temporarily pause non-critical producers to let the queue recover.

4. Verification

  1. Confirm email retry queue depth has been below the warning threshold for at least 10 minutes.
  2. Confirm the affected business services are healthy on the dashboard.
  3. Confirm no alerts remain open for this component and its downstream consumers.
  4. Spot-check one real end-to-end operation through the affected flow.

5. Rollback / restore

  1. If a deploy caused the incident, roll back to the previous release and re-verify.
  2. If a configuration or threshold change caused it, restore the previous value and record why.
  3. Re-enable any job, feature flag or channel that was paused during mitigation, one at a time.

Escalation path

  • First responder: NOC on duty — acknowledge within 5 minutes.
  • Component owner: Notification Team.
  • Escalation owner (page on critical): Notification Team.
  • Escalate if the metric is still critical 15 minutes after mitigation, or if data integrity is in doubt.
  • Declare a major incident if two or more critical components are alerting at the same time.

Blast radius — business services affected (1)

Email Notifications

External dependencies

Zoho Mail / ZeptoMail — Transactional email delivery

Simulated incidents that exercise this runbook

Email delivery degradation — Zoho email rejecting sends; invites, receipts and notices delayed.

Reporting notes

  • Record start time, actions taken and recovery time in the incident record.
  • Attach the dashboard screenshot and the dominant error message to the postmortem.
  • Content drafted for the monitoring demo — confirm the exact commands with the owning team before production use.