Final Update: Thursday, 17 February 2022 07:33 UTC
We've confirmed that all systems are back to normal with no customer impact as of 12/17, 06:35 UTC. Our logs show the incident started on 12/16, 16:16 UTC and that during the 14 hours and 20 minutes that it took to resolve the issue, some customers using Azure Log Analytics and Log Search Alerts in East US region may have experienced data latency for certain data types and missed alerts.
Root Cause: The failure was due to an issue in backend dependent service.
Incident Timeline: 14 Hours & 20 minutes - 12/16, 16:16 UTC through 12/17, 06:35 UTC
We understand that customers rely on Azure Log Analytics and Log Search Alerts as a critical service and apologize for any impact this incident caused.
Update: Thursday, 17 February 2022 04:08 UTC
Root cause has been isolated to configuration which was impacting logs ingestion. To address this issue we have redeployed service. Some customers may experience data latency for certain data types and missed alerts. and we estimate 4 hours before all backlog of data is addressed.