# Inefficient use of RDS reader nodes | Cloud Efficiency Hub Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/inefficient-use-of-rds-reader-nodes RDS reader nodes are intended to handle read-only workloads, allowing for traffic offloading from the primary (writer) node. By: Jim Bendoraitis Updated: 2026-09-28 [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) # Inefficient Use of RDS Reader Nodes The short version RDS reader nodes are intended to handle read-only workloads, allowing for traffic offloading from the primary (writer) node. [Jim Bendoraitis](https://www.linkedin.com/in/jim-bendoraitis-44b798b1/) Senior Manager, Platform Engineering @ United Airlines AWS service [AWS RDS](https://www.pointfive.co/efficiency-hub/cloud-services/aws-rds) Category [Databases](https://www.pointfive.co/efficiency-hub/service-category/databases) Reference CER-0205 Type Inefficient Architecture ## Explanation Why the waste happens and who it affects. 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. ## Billing model The pricing dimensions that drive this cost. Per-instance hourly cost for each provisioned writer and reader node ## How to detect 5 checks to find it in your estate. - Review whether the resource has been actively used over a representative time period - Compare the volume of read traffic across reader nodes vs. the writer node - Identify services that are hardcoded to target the writer node for both read and write operations - Evaluate whether the presence of reader nodes is necessary if they are consistently underutilized - Assess application architectures for abstraction layers or configuration patterns that bypass proper routing to readers ## How to fix 4 ways to remove the waste. - Refactor application logic or database client configurations to route read traffic to reader endpoints - Introduce or enhance query routing layers (e.g., using database drivers with read/write splitting support) - Remove or downsize reader nodes if there is no realistic path to utilizing them efficiently, after confirming they are not needed for availability: Aurora promotes a reader if the writer fails, and an RDS Multi-AZ DB cluster always has two reader instances that act as failover targets - Monitor reader vs. writer utilization continuously to ensure traffic is appropriately distributed ## Documentation Vendor references for pricing and configuration. - [Working with DB instance read replicas docs.aws.amazon.com](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html) - [Best practices for Amazon RDS docs.aws.amazon.com](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_BestPractices.html) - [Amazon Aurora endpoint connections docs.aws.amazon.com](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Overview.Endpoints.html) - [Replication with Amazon Aurora docs.aws.amazon.com](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Replication.html) - [Multi-AZ DB cluster deployments for Amazon RDS docs.aws.amazon.com](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - AWS RDS CER-0323 ### [RDS SQL Server Running Bundled Licensing on Older Instance Families](https://www.pointfive.co/efficiency-hub/inefficiencies/rds-sql-server-running-bundled-licensing-on-older-instance-families) Amazon RDS for SQL Server has traditionally used a License Included model where the SQL Server license cost is bundled into a single hourly instance price alongside Windows OS licensing, compute resources, and RDS management capabilities.... Databases - AWS RDS CER-0322 ### [Non-Production RDS SQL Server Using Standard or Enterprise Edition Instead of Developer Edition](https://www.pointfive.co/efficiency-hub/inefficiencies/non-production-rds-sql-server-using-standard-or-enterprise-edition-instead-of-developer-edition) Amazon RDS for SQL Server uses a License Included pricing model where the hourly instance rate bundles Microsoft SQL Server licensing fees on a per-vCPU basis. When non-production workloads - such as development, testing, staging, QA, or... Databases - AWS RDS CER-0320 ### [Excess vCPU Licensing Costs on RDS for SQL Server Instances](https://www.pointfive.co/efficiency-hub/inefficiencies/excess-vcpu-licensing-costs-on-rds-for-sql-server-instances) Amazon RDS for SQL Server uses a License Included pricing model where SQL Server and Windows OS licensing costs are bundled into the per-instance-hour rate - and those licensing costs scale directly with the number of vCPUs on the... Databases --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.