Here,s why the other options are not ideal:
A). Create one load balancer per AD with separate backend pools: This creates single points of failure in each AD. If a load balancer in an AD fails, traffic wouldn,t be routed to other ADs, impacting availability.C. Regional load balancers are currently not available in OCI, so this option isn,t applicable.D. High availability groups within a single AD: While this ensures redundancy within the AD, it doesn,t address potential failures across different ADs, limiting true multi-region HA.By configuring a single load balancer with backend servers spanning multiple ADs, you achieve several benefits:
High availability: If a backend server in one AD fails, the load balancer can direct traffic to healthy servers in other ADs, minimizing downtime and impact on users.
Centralized management: You manage a single load balancer, simplifying configuration and monitoring.
Efficient traffic distribution: The load balancer can intelligently distribute traffic across all available backend servers, regardless of AD, based on its load balancing algorithm.