We've confirmed that all systems are back to normal with no customer impact as of 06/21, 02:20 AM UTC. Our logs show the incident started on 06/21, 00:20 AM UTC and that during the duration that it took to resolve the issue customers experienced intermittent failures and data gaps in earlier time periods when retrieving metric data through the Azure portal or when retrieving data programmatically
Root Cause: A backend service in the query pipeline became degraded due to unexpected workload.
Incident Timeline: 06/21, 00:20 AM UTC through 06/21, 02:20 AM UTC
We understand that customers rely on Azure Monitor as a critical service and apologize for any impact this incident caused.