FortiMonitor is a holistic, SaaS-based digital experience and network performance monitoring solution which combines monitoring, network incident management, automation, and network configuration management into a single source of truth
Article Id 227550
Description This article describes two different scenarios in which OnSight load balancing can occur. 
Scope FortiMonitor, OnSight.

Scenario 1.

The first scenario describes an OnSight in high availability (HA) cluster performing a temporary failover. 




1) OnSight must be in the same HA pair or the OnSight group.

2) The instance agent has 'Monitoring Location' as one of the OnSight in HA pair. 


A few scenario considerations: 


1) The first OnSight name can be considered as 'OnSight 1' and the second OnSight as 'OnSight 2'.

2) One of the OnSights is not able to sync and there is an OnSight heartbeat (HB) alert.  


For current instances and metrics that have 'Monitoring Location' set to OnSight 1, there will be a failover of metrics performed if OnSight 1 is unable to sync (or there is an OnSight HB alert).

When this incident occurs, the HA cluster will automatically failover to the next available OnSight temporarily in the backend.

As a result, the 'Monitoring Location' of the instance will not be changed on the user interface despite OnSight 2 conducting the checks instead of OnSight 1.

Once OnSight 1 can sync successfully again, the checks will be moved back to OnSight 1.  


Scenario 2.

The second scenario explains when an OnSight will load balance due to metric count. 



OnSights must be in same HA pair on OnSight group.  


A few scenario considerations:  


1) The total metric count (SNMP and Network) of both the OnSights are the same. 

2) The first OnSight name can be considered as 'OnSight 1' and second OnSight as 'OnSight 2'.

3) Both OnSights are active and there are no OnSight HB alerts.


For new network or SNMP instances that are getting onboarded and have 'Monitoring Location' set as OnSight 1 (at the instance and metric level), checks will be performed on the backend that compares the total number of checks for each OnSight.

If the difference between OnSight 1 and OnSight 2 is significant, the FortiMonitor OnSight will try to load balance the metrics.

This means that the monitoring location at both the server and metric level will be switched to OnSight 2 permanently. 

Unlike Scenario 1, this change in monitoring location is formal as this action is not considered to be temporary. 


A few key points to remember related to Scenario 2:

1) Currently, FortiMonitor calculates the total metric count for 'SNMP' and 'network' checks on each Onsight within the HA group and then load balances the metrics.  

2) FortiMonitor checks every two hours to identify if there is a need for the load balancing of metrics (network and SNMP) within the OnSight HA cluster.