In anN+1 High Availability (HA)configuration, a single secondary Control and Application (CA) server provides backup for multiple primary CA servers. The FortiNAC-F Manager (FortiNAC-M) acts as the centralized orchestrator for this cluster, monitoring the health of all participating nodes.
According to theFortiNAC-F 7.6.0 N+1 Failover Reference Manual, when a primary CA (such asCA-2in the exhibit) fails, the secondary CA (CA-3) is automatically promoted by the Manager to take over the specific workload and database functions of that failed primary. Crucially, the documentation specifies that even after this promotion, the system architecture maintains its N+1 logic. The secondary CA effectively " assumes the identity " of the failed primary while continuing to operate within the N+1 framework established by the Manager.
It doesnotmerge with CA-1 to form a traditional 1+1 active/passive cluster (A), nor does it engage in load balancing (D), as FortiNAC-F HA is designed for redundancy and failover rather than active traffic distribution. Furthermore, CA-3 does not " share " management with CA-1 (C); it independently handles the tasks originally assigned to CA-2. Throughout this failover state, the Manager continues to oversee the group, and CA-3 remains the designated secondary unit currently acting in a primary capacity for the downed node until CA-2 is restored.
" In an N+1 Failover Group, theSecondary CAis designed to take over the functionality ofany single failed primary componentwithin the group. The FortiNAC Manager monitors the primaries and initiates the failover to the secondary... Once failover occurs, the secondary continues to operate as the backup unit for the failed primary while remaining part of the managed N+1 HA configuration. " -FortiNAC-F 7.6.0 N+1 Failover Reference Manual: Failover Behavior Section.