We've confirmed that all systems are back to normal with no customer impact as of 7/10, 21:00 UTC. Our logs show the incident started on 7/10, 07:40 UTC and that during the 13 hours and 20 minutes that it took to resolve the issue 82.8% of customers in East US region have experienced an increased latency greater than 1 hour.
Root Cause: The failure was due to the issue with one of our backend service. Incident Timeline: 13 Hours 20 minutes - 7/10, 07:40 UTC through 7/10, 21:00 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.