With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgHaStatsHostname
fg Ha Stats Hostname
1.3.6.1.4.1.12356.101.13.2.1.1.11
Host name of the specified cluster member
Back to FORTINET-FORTIGATE-MIB MIB page.
IPHost Network monitor allows you to monitor fgHaStatsHostname on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet switches right now.