We've confirmed that all systems are back to normal with no customer impact as of 10/1, 18:12 UTC. Our logs show the incident started on 10/1, 16:30 UTC and that during the 1 hour and 42 minutes that it took to resolve the issue 5.5% of customers experienced query failures for log analytics data as well as possible unexpected missing or triggered log search alerts.
Root Cause: The failure was a result of unexpected errors on several backend processor nodes reducing the overall availability of the resource to process requests.
Incident Timeline: 1 Hours & 42 minutes
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Initial Update: Tuesday, 01 October 2019 17:55 UTC
We are aware of issues within Log Analytics and are actively investigating. Some customers may be experiencing query failures and delayed ingestion in East US region.
Next Update: Before 10/01 20:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jeff