Final Update: Tuesday, 21 December 2021 23:31 UTC
We've confirmed that all systems are back to normal with no customer impact as of 12/21, 22:57 UTC. Our logs show the incident started on 12/21 18:01 UTC and that during the entire duration that it took to resolve the issue customers from Log Analytics, Log Search alerts and/or Azure Sentinel experienced data latency, delayed or missing alerts and incorrect metrics when trying to access the data from region West Central US.
- Root Cause: The failure was due to dependent downstream service which was degraded due to a configuration change.
- Mitigation Step: The owning service applied a configuration change and issues started mitigating.
- Incident Timeline: 12/21, 18:01 UTC through 12/21, 22:57 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
-Arish Balasubramani