RDS reader nodes are intended to handle read-only workloads, allowing for traffic offloading from the primary (writer) node. However, in many environments, services are misconfigured or hardcoded to send all traffic—including reads—to the writer node. This results in underutilized reader nodes that still incur full hourly charges, while the writer node becomes a performance bottleneck and may require upsizing to handle unnecessary load. This inefficiency reduces cost-effectiveness and resilience, especially in high-throughput or scalable architectures.
Per-instance hourly cost for each provisioned writer and reader node
