We've confirmed that all systems are back to normal with no customer impact as of 10/13, 05:30 UTC. Our logs show the incident started on 10/13, 01:50 UTC and that during the 3 hours 40 minutes that it took to resolve the issue some customers in East US region may have experienced data access issues in Azure and OMS portal for Log analytics.
Root Cause: The failure was due to Azure Storage outage in East US region.
Incident Timeline: 3 Hours & 40 minutes - 10/13, 01:50 UTC through 10/13, 05:30 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Initial Update: Saturday, 13 October 2018 04:23 UTC
We are aware of issues within Log Analytics and are actively investigating. Customers in East US may experience ingestion delays starting from Saturday, 13 October 2018 6:50 PST.
Next Update: Before 10/13 06:30 UTC
We are working hard to resolve this issue and apologize for any inconvenience.