RDS Multi-AZ vs Read Replicas

Understand the difference between high availability (Multi-AZ) and read scaling (Read Replicas).

Multi-AZ = synchronous standby in another AZ for automatic failover (availability, not scaling).

Read Replicas = asynchronous copies that serve read traffic (scaling, not automatic failover).

Exam trap: if the requirement is high availability, choose Multi-AZ; if it is offloading read traffic, choose Read Replicas.