We've confirmed that all systems are back to normal with no customer impact as of 3/20, 04:05 UTC. Our logs show the incident started on 3/20, 01:36 UTC and that during the 2 hours 29 minutes that it took to resolve the issue 100% of customers experienced query failures in USGov Virginia.
Root Cause: The failure was due to a software update on a backend service that caused unexpected problems in the cluster.
Incident Timeline: 2 Hours & 29 minutes - 3/20, 01:36 UTC through 3/20, 04:05 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Initial Update: Wednesday, 20 March 2019 02:38 UTC
We are aware of issues within Log Analytics in the Fairfax region and are actively investigating. Some customers may be experiencing query failures.
Work Around: None at this time
Next Update: Before 03/20 05:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jeff Miller