Connect to the GUI of the primary FortiGate. The HA Status widget shows the cluster mode (Mode) and group name (Group).
It also shows the host name of the primary FortiGate, which you can hover over to verify that the cluster is synchronized and operating normally. You can click on the widget to change the HA configuration or view a list of recently recorded cluster events, such as members joining or leaving the cluster.
To view the cluster status, click on the HA Status widget and select Configure settings in System > HA (or go to System > HA).
If the cluster is part of a Security Fabric, the FortiView Physical and Logical Topology views show information about the cluster status.