All custom alerts are suspended during maintenance windows.

The following performance-related alerts are also suspended during maintenance windows:

Host machine alerts

• Physical memory
• Processor under-utilization
• Processor utilization

SQL Server alerts

• Blocking process
• Custom metric collection error
• Database unavailable
• Deadlock
• Job duration unusual
• Long-running query

Availability group alerts

• Availability group - query slowdown
• Availability group - replication falling behind