Amazon Aurora vs RDS: Which Managed Database Is Right for You?

Introduction

For organizations running relational databases on AWS, the choice between Amazon Aurora and Amazon RDS is one of the most common architectural decisions. Both are excellent managed database services that handle provisioning, patching, backup, and recovery. But they have significant differences in performance, architecture, cost, and feature sets. This comparison helps you make the right choice.

Architecture Differences

Amazon RDS uses a traditional database architecture: your database instance runs on an EC2 instance attached to EBS storage. Storage grows by provisioned amounts, and failover involves promoting a standby instance which can take minutes.

Amazon Aurora uses a completely different, cloud-native architecture. The storage layer is decoupled from the compute layer: a distributed, fault-tolerant storage system spanning three Availability Zones, automatically scales in increments of 10 GB, and requires no storage provisioning. Failover to a read replica typically completes in 30 seconds or less.

Performance Comparison

Aurora typically outperforms RDS by significant margins for the same instance size. AWS benchmarks show Aurora delivering up to 5x the throughput of MySQL on RDS and up to 3x the throughput of PostgreSQL on RDS.

This performance advantage comes from Aurora’s optimized write path, which requires only 4 of 6 storage nodes to acknowledge a write (vs. waiting for a full disk flush in traditional databases) and its efficient use of network I/O.

For write-heavy applications or those requiring maximum throughput, Aurora often provides significantly better performance at comparable cost.

Cost Comparison

Aurora is generally more expensive per instance-hour than equivalent RDS instances. However, Aurora’s superior performance often means you can achieve the same throughput with a smaller Aurora instance than you would need with RDS, which can offset the higher per-hour cost.

Aurora Serverless is a cost-effective option for applications with variable or intermittent usage, automatically scaling compute up and down (or to zero when not in use) based on actual demand. Ozy Solutions helps clients model and compare costs for Aurora vs RDS for their specific workloads.

When to Choose Aurora

Choose Aurora when you need: maximum performance from a MySQL or PostgreSQL-compatible database, high availability with fast failover, global database capabilities with multi-region replication, or serverless scaling for variable workloads.

Aurora Global Database replicates your data across multiple regions with less than 1 second latency, enabling fast local reads globally and disaster recovery with recovery time objectives of under 1 minute.

When to Choose RDS

Choose RDS when you need: Oracle or SQL Server, which are not available in Aurora. Also choose RDS when you are migrating an existing database with specific configurations that may not work with Aurora, or when you need the exact version of MySQL or PostgreSQL that your application requires and Aurora does not support it.

For most new MySQL and PostgreSQL workloads, Aurora is the recommended starting point. Visit our Ozy Solutions blog for detailed comparisons and migration guides.

Conclusion

Both Aurora and RDS are excellent managed database services. Aurora’s cloud-native architecture delivers superior performance, availability, and scalability for MySQL and PostgreSQL workloads. RDS offers broader database engine support and compatibility for existing applications. Ozy Solutions’ AWS database management team can evaluate your specific requirements and recommend the best option.