How are the metrics calculated in agentless server monitoring?

How are the metrics calculated in agentless server monitoring?

SNMP server monitoring

Metrics such as CPU, Memory, and Disk utilization are collected via SNMP using the OIDs given below:









Free Disk Space (MB) 


Used Disk Space (MB)  


Disk Partition 


If you do not see the metrics being displayed in the web client, please check if the server responds to SNMP GET requests for the above mentioned OIDs as described here.

WMI server monitoring

CPU, Memory, and Disk metrics are collected using the queries given below:
WMI Query
CPU Metrics
SELECT LoadPercentage, DeviceID FROM Win32_Processor
Memory Metrics
SELECT FreePhysicalMemory,TotalVisibleMemorySize FROM Win32_OperatingSystem
Disk Metrics
Select * from Win32_LogicalDisk where DriveType=3 or DriveType=4
You can execute WMI queries as described here

Individual disk metrics: 

Individual disk metrics are collected by executing the Visual Basic Script available in the following path:
{Site24x7 On-Premise Poller installed directory}/NetworkPlus/conf/OpManager/application/scripts/disk.vbs 

To test the above, execute the file in the Command Prompt (as Administrator) as follows:
disk.vbs <Target IP/Host Name> <UserName> <Password>