We've confirmed that all systems are back to normal with no customer impact as of 04/30, 22:55 UTC. Our logs show the incident started on 04/30, 18:50 UTC and that during the 4 hours 5 minutes that it took to resolve the issue some of customers in South UK region might have experienced data latency and data gap issues for Log Analytics and Service Map.
Root Cause: The failure was due to the issue in one of our dependent services.
Incident Timeline: 4 Hours & 5 minutes - 04/30, 18:50 UTC through 04/30, 22:55 UTC
We understand that customers rely on Azure Log Analytics and Service Map as a critical services and apologize for any impact this incident caused.
Update: Thursday, 30 April 2020 23:11 UTC
We are investigating issues within Log Analytics and Service Map. Root cause is not fully understood at this time. Some customers continue to experience data latency and data gaps issues in South UK. We are working to establish the start time for the issue, initial findings indicate that the problem began at 04/30 ~18:50 UTC. We currently have no estimate for resolution.