Amazon Aurora versus RDS – Key Differences

Amazon Relational Database Service (RDS) and Amazon Aurora are both managed relational database services offered by AWS, but they cater to different needs and have several distinguishing characteristics.  

We discuss the key differences between Amazon Aurora and RDS.

Engine Options

• RDS: Supports several database engines, including MySQL, PostgreSQL, MariaDB, Oracle, and Microsoft SQL Server.
• Aurora: It’s essentially a part of RDS but is a custom-built database engine by AWS. Aurora is compatible with MySQL and PostgreSQL, meaning you can use the same code, applications, drivers, and tools.

Performance

• RDS: Provides standard performance based on the specific database engine you choose.
• Aurora: Claims up to 3 times the throughput of standard MySQL running on RDS and up to 2 times the throughput of standard PostgreSQL.

Storage Architecture

• RDS: Uses standard block storage, depending on the engine and the storage type you choose (like General Purpose, Provisioned IOPS, or Magnetic).
• Aurora: Has a unique distributed, fault-tolerant, self-healing storage system that auto-scales up to 64TB per database instance. It replicates data six ways across three Availability Zones.

Replication

• RDS: Supports read replicas for scaling read operations and standby replicas in another availability zone for failover in certain engines.
• Aurora: Supports up to 15 read replicas with sub-10ms replica lag, which can be promoted to the primary without any data loss. Also, Aurora automatically handles the failover in the event of a primary instance failure.

Availability & Durability

• RDS: Uses Multi-AZ deployments and automated backups to enhance availability and durability.
• Aurora: Continuously backs up data to Amazon S3 and transparently recovers from physical storage failures; instance failover typically takes less than 30 seconds.

Pricing

• RDS: Pricing depends on the database engine, instance type, and additional features such as Multi-AZ deployments or Provisioned IOPS.
• Aurora: Generally has a different pricing model compared to standard RDS and can be more cost-effective at scale.

Serverless Option

• RDS: Doesn’t have a native serverless option.
• Aurora: Offers Aurora Serverless, which automatically adjusts database capacity based on actual usage, making it suitable for variable or unpredictable workloads.

Customizability

• RDS: Provides parameter groups to customize database settings based on the chosen engine.
• Aurora: While it also uses parameter groups, certain advanced features, and configurations might be specific to Aurora and unavailable in traditional RDS engines.

Maintenance

• RDS: Regular maintenance windows, with the option to control times and apply upgrades.
• Aurora: Automated software patching with a brief interruption, typically less than 30 seconds.

Conclusion

In summary, while Amazon Aurora and RDS provide managed relational database services, Aurora is AWS’s custom-built solution offering enhanced performance and availability, as well as some advanced features not available in standard RDS.

However, RDS provides a broader choice of database engines and is more familiar to organizations that want a more traditional database management experience.

Amazon Aurora versus RDS – 7 mins