HA Reserved Management Interface
https://community.fortinet.com/t5/FortiGate/Technical-Tip-HA-Reserved-Management-Interface/ta-p/190132
SNMP HA-Direct
https://community.fortinet.com/t5/FortiGate/Technical-Tip-SNMP-communication-working-scenario-with-respect/ta-p/214350
HA Upgrade
https://community.fortinet.com/t5/FortiGate/Technical-Tip-FortiGate-HA-upgrade-procedure-and-the-status/ta-p/246692
