We've confirmed that all systems are back to normal with no customer impact as of 01/16, 15:20 UTC. Our logs show the incident started on 01/16, 10:15 UTC and that during the 5 hours 5 minutes that it took to resolve the issue some of customers experienced alerting delays and missed alerts for Log Search Alerts and increased latency for log data availability for Azure Log Analytics.
Root Cause: The failure was due to an issue with one of our dependent service.
Incident Timeline: 5 Hours & 5 minutes - 01/16, 10:15 UTC through 01/16, 15:20 UTC
We understand that customers rely on Log Search Alerts and Azure Log Analytics as critical services and apologize for any impact this incident caused.
Initial Update: Thursday, 16 January 2020 12:21 UTC
We are aware of issues within Log Search Alerts and are actively investigating. Some customers in East US 2 region may experience alerting delays and missed alerts.
Work Around: None
Next Update: Before 01/16 15:30 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Monish