What is the difference between Amazon RDS and Aurora, and when should you use each?

Amazon RDS and Aurora are both managed relational database services from AWS, but they differ significantly in architecture, performance, and capabilities.

Amazon RDS

RDS is a managed service that handles common database administration tasks for traditional database engines.

Supported Engines

• MySQL, PostgreSQL, MariaDB
• Oracle, Microsoft SQL Server
• Db2

Architecture

• Traditional single-server or Multi-AZ setup
• Synchronous replication for Multi-AZ standby
• Standard EBS storage (gp2, io1)
• Up to 5 read replicas

Key Features

• Automated backups, patching, monitoring
• Multi-AZ for high availability (standby not readable)
• Point-in-time recovery
• Familiar database engine compatibility

Amazon Aurora

Aurora is a cloud-native relational database engine built from the ground up for cloud performance and availability.

Supported Engines

• Aurora MySQL (compatible with MySQL 5.7/8.0)
• Aurora PostgreSQL (compatible with PostgreSQL)

Architecture

• Distributed, shared storage layer across 6 copies in 3 AZs
• Storage automatically scales from 10GB to 128TB
• Up to 15 Aurora Replicas (all readable)
• Continuous backup to S3

Performance Advantages

• 5x throughput vs MySQL RDS
• 3x throughput vs PostgreSQL RDS
• Faster failover: typically under 30 seconds

Additional Features

• Aurora Serverless: Auto-scales compute up/down to zero
• Aurora Global Database: Multi-region replication with < 1 second lag
• Aurora Multi-Master: Multiple read-write instances
• Backtrack: Roll back database to specific point without restore

Comparison

When to Use Each

Use RDS when:

• Running Oracle or SQL Server (no Aurora equivalent)
• Cost is primary concern for small workloads
• You need exact MySQL/PostgreSQL feature compatibility

Use Aurora when:

• High performance and availability are critical
• Multi-region replication required
• Serverless or variable workload patterns
• Large-scale workloads > 5 read replicas needed