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Alert Timing & Delivery Reference

Understand exactly when your alerts fire, repeat, and resolve across notification channels. Quick reference for alert timing behavior with threshold alerts, anomaly detection, and SLO violations.

Get alerts when you need them. Here’s exactly when notifications fire, repeat, and resolve across your channels.

Quick Reference

Threshold & Anomaly Alerts

  • First alert: 2 minutes after threshold breach
  • Repeat alerts: Every 61 minutes while active
  • Resolution: 11 minutes after condition clears

SLO Alerts

  • First alert: 4 minutes after SLO violation
  • Repeat alerts: Every 16 minutes while active
  • Resolution: 31 minutes after SLO recovers

How Alert Timing Works

When something goes wrong at timestamp t-1, here’s the timeline:

Threshold & Anomaly Alerts

t-1: Issue occurs (CPU spikes, error rate jumps)
t+1: Last9 generates the alert
t+2: Notification hits your channel
t+61: Reminder
recovery+11: Resolution

Alert Timing — Threshold & Anomaly Alerts

SLO Alerts

t-1: SLO violation begins (error budget burned)
t+3: Last9 generates the alert
t+4: Notification hits your channel
t+16: Reminder
recovery+31: Resolution

Alert Timing — SLO Alerts

Notification Channels

Threshold & Anomaly Alerts: All channels (Slack, PagerDuty, OpsGenie, Webhook, Email)
SLO Alerts: Slack, PagerDuty, OpsGenie, Webhook only (Email not supported)

All supported channels follow the same timing behavior:

Alert TypeFirst NotificationRepeat FrequencyResolution Delay
Threshold/Anomalyt+2 minutesEvery 61 minutes11 minutes
SLO Violationt+4 minutesEvery 16 minutes31 minutes

Why These Delays?

  • Processing time: Last9 needs 1-3 minutes to analyze metrics and confirm alert conditions
  • Delivery buffer: 1-minute buffer accounts for network latency and channel processing
  • Resolution delays: Prevents flapping alerts when conditions briefly recover then fail again

Examples

Scenario: API response time spikes at 1:59 PM

  • 2:01 PM: Last9 confirms threshold breach
  • 2:02 PM: Webhook fires, Slack notification arrives
  • 3:01 PM: Reminder if still alerting
  • When fixed + 11 min: Resolution notification

Scenario: Error budget burns through at 3:14 PM

  • 3:18 PM: Last9 confirms SLO violation
  • 3:19 PM: Slack/PagerDuty/Webhook notifications sent (Email not supported for SLO)
  • 3:31 PM: First reminder if still violating
  • When recovered + 31 min: Resolution notification

Troubleshooting

Please get in touch with us on Discord or Email if you have any questions.