We've confirmed that all systems are back to normal with no customer impact as of 02/17, 12:30 UTC. Our logs show the incident started on 02/15, 15:00 UTC and that during the 45 hours & 30 minutes that it took to resolve the issue Some customers may have experienced data loss issue in azure portal for some data types in South UK region.
Root Cause: The failure was due issues with one of our dependent service.
Incident Timeline: 45 Hours & 30 minutes - 02/15, 15:00 UTC through 02/17, 12:30 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Update: Monday, 17 February 2020 12:00 UTC
We continue to investigate issues within Log Analytics. Root cause is not fully understood at this time. Some customers may experience data loss issue in azure portal for some data types in South UK region. We are working to establish the start time for the issue, initial findings indicate that the problem began at 02/15 15:00 UTC. We currently have no estimate for resolution.