Explanation
Active/Active high availability is a deployment mode that allows both firewalls in an HA pair to actively process traffic and share the load. Active/Active HA is suitable for environments that require real, full-time redundancy from both firewalls at all times, as there is no failover time or session loss in case of a firewall failure. Active/Active HA is also suitable for environments that require that both firewalls maintain their own routing tables for faster dynamic routing protocol convergence, as each firewall can run its own routing protocols and exchange routes with other routers independently. Active/Active HA is also suitable for environments that require that traffic be load-balanced across both firewalls to handle peak traffic spikes, as each firewall can process a portion of the traffic and increase the overall throughput and performance.
Active/Active HA is not suitable for environments that require Layer 2 interfaces in the deployment, as Layer
2 interfaces are not supported in Active/Active HA mode. Active/Active HA is also not suitable for environments that require that all configuration must be fully synchronized between both members of the HA pair, as some configuration settings are not synchronized in Active/Active HA mode, such as virtual router configuration, virtual wire configuration, and QoS configuration. References: :
https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/set-up-activeactive-ha :
https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/high-availability/set-up-activeactive-ha/determine-