AWS RDS vs Aurora: A Comprehensive Comparison
Executive Summary
AWS offers two primary managed database services: Amazon RDS (Relational Database Service) and Amazon Aurora. While both services provide managed relational databases, they serve different needs in terms of performance, scalability, and cost. This comparison will help you make an informed decision based on your specific requirements.
What is Amazon RDS?
Amazon RDS is a managed relational database service that makes it easy to set up, operate, and scale relational databases in the cloud. It provides cost-efficient and resizable capacity while automating time-consuming administration tasks such as hardware provisioning, database setup, patching, and backups.
What is Amazon Aurora?
Amazon Aurora is a MySQL and PostgreSQL-compatible relational database built for the cloud, that combines the performance and availability of traditional enterprise databases with the simplicity and cost-effectiveness of open-source databases. It delivers up to five times the throughput of standard MySQL and up to three times the throughput of standard PostgreSQL.
Technical Deep Dive
Amazon RDS
RDS is a managed service that supports six popular database engines:
- MySQL
- PostgreSQL
- MariaDB
- Oracle
- Microsoft SQL Server
- Amazon Aurora
Amazon Aurora
Aurora is a cloud-native database engine that's compatible with MySQL and PostgreSQL. It uses a distributed, fault-tolerant, self-healing storage system that auto-scales up to 128TB per database instance.
Feature Comparison
| Feature | RDS | Aurora |
|---|---|---|
| Database Engines | MySQL, PostgreSQL, MariaDB, Oracle, SQL Server | MySQL, PostgreSQL |
| Storage Type | EBS (Elastic Block Store) | Custom distributed storage |
| Maximum Storage | 64TB | 128TB |
| Read Replicas | Up to 5 | Up to 15 |
| Backup Retention | Up to 35 days | Up to 35 days |
| Point-in-Time Recovery | Yes | Yes |
| Multi-AZ Deployment | Yes | Yes |
Cost Comparison
| Cost Component | RDS | Aurora |
|---|---|---|
| Instance Cost | Lower | Higher |
| Storage Cost | Higher | Lower |
| I/O Cost | Per I/O request | Included in storage |
| Backup Storage | Beyond free tier | Beyond free tier |
Pros and Cons
Amazon RDS Pros
- Supports multiple database engines
- Lower instance costs
- Simpler architecture
- Better for smaller workloads
- More flexible instance types
Amazon RDS Cons
- Lower performance compared to Aurora
- Limited scalability
- Higher storage costs
- More I/O operations needed
Amazon Aurora Pros
- Higher performance (up to 5x MySQL, 3x PostgreSQL)
- Better scalability
- Lower storage costs
- More read replicas
- Better fault tolerance
Amazon Aurora Cons
- Higher instance costs
- Limited to MySQL and PostgreSQL
- More complex architecture
- May be overkill for smaller workloads
Risks and Considerations
Amazon RDS Risks
- Performance limitations for high-throughput applications
- Storage I/O bottlenecks
- Limited read scaling capabilities
- Potential for higher operational costs at scale
Amazon Aurora Risks
- Higher initial costs
- Complexity in management
- Potential for over-provisioning
- Limited database engine options
Use Case Recommendations
Choose RDS when:
- You need specific database engines (Oracle, SQL Server)
- Your workload is moderate
- Cost is a primary concern
- You need simpler architecture
Choose Aurora when:
- You need high performance
- Your workload is large or growing
- You need better scalability
- You're using MySQL or PostgreSQL