In our company, we are doing the below set of things to check whether DC is happening properly.
1. Reports -> Monitor Status Report
For demo, www.site24x7.com/app/demo#/reports/SERVER/current-status
This will give you a list of Server Monitors with an attribute called last polled time. Using that you will be able to identify the monitors whose data collections are not happening. If the the poll interval is 5/1 min and last polled time is more than 10 mins, it means DC is not happening in those Servers
2. Home -> Dashboards -> Custom Dashboard
Choose Widget Category - Current Status Widget
Choose Resource Type - Monitor Type (Server Monitor)
Filter by Status - Select All
Drag widgets to dashboard - Monitors in Monitor Type (Drag this to the main window)
You will be able to see the current status of all the Server Monitors. If a particular server monitor goes down because of data collection problem , you will be able to identify them using the NOC view at a glance.