We've confirmed that all systems are back to normal with no customer impact as of 10/12, 18:20 UTC. Our logs show the incident started on 10/12, 15:55 UTC and that during the two and a half hours that it took to resolve the issue 25% of customers in the North Europe region experienced delayed or mis-fired Log Search Alerts, delays with Service Map data, and failures trying to query Log Analytics data.
Root Cause: The failure was due to a back end component becoming unhealthy. When this component was restarted manually, it returned to health.
Incident Timeline: 2 Hours & 25 minutes - 10/12, 15:55 UTC through 10/12, 18:20 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Initial Update: Monday, 12 October 2020 17:51 UTC
We are aware of issues within Log Analytics and are actively investigating. Some customers may experience alerting failures (false alerts or alerts that do not fire) as well as issues with Service Map and querying Log Analytics data.
Next Update: Before 10/12 19:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jack Cantwell