When should I choose Aurora over RDS?

Choose Aurora when high availability is critical (sub-30s failover), for read-heavy workloads (up to 15 replicas with ms lag), variable workloads (Serverless v2), global applications (Global Database with sub-1s replication), or when you need fast cloning for dev/test.

When should I choose RDS over Aurora?

Choose RDS for cost-sensitive workloads (20-30% cheaper), when you need Oracle/SQL Server/MariaDB engines, for simple workloads that don't need Aurora's advanced features, or for predictable I/O costs with gp3 storage.

AWS Aurora vs RDS – Performance & Cost Comparison

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AWS Aurora vs RDS – MySQL & PostgreSQL

Aurora vs RDS Comparison

When to Choose Aurora

When to Choose RDS

AWS Certification Exam Practice Questions

Both Amazon Aurora and Amazon RDS provide managed relational database services, but Aurora is AWS’s cloud-native redesign with significantly different architecture.

Aurora is compatible with MySQL and PostgreSQL but delivers up to 5x throughput of MySQL and 3x of PostgreSQL on the same hardware.
Choice depends on performance requirements, cost tolerance, and need for advanced features like global databases or serverless scaling.

Aurora vs RDS Comparison

Feature	Amazon Aurora	Amazon RDS (MySQL/PostgreSQL)
Architecture	Cloud-native, distributed storage (6 copies across 3 AZs)	Traditional architecture with EBS-based storage
Performance	5x MySQL, 3x PostgreSQL throughput	Standard MySQL/PostgreSQL performance
Storage	Auto-scales 10GB to 128TB, no pre-provisioning	Provision up to 64TB (gp3/io1/io2)
Replication	Up to 15 read replicas, millisecond lag	Up to 15 read replicas, seconds to minutes lag
Failover	<30 seconds (shared storage, no data sync needed)	60-120 seconds (Multi-AZ DNS failover)
Multi-AZ	Built-in (storage spans 3 AZs by default)	Synchronous standby in separate AZ
Global Database	Yes – cross-region replication <1 second lag	Cross-region read replicas (minutes lag)
Serverless	Aurora Serverless v2 (scales to 0 ACU, instant scaling)	Not available
Backtrack	Yes – rewind DB to any point in seconds (MySQL only)	Not available (use point-in-time restore)
Cloning	Fast clone using copy-on-write (seconds, no storage cost initially)	Snapshot restore (minutes to hours)
Blue/Green Deployments	Yes	Yes
Cost	~20-30% more than RDS for same instance size	Lower base cost
I/O Cost	Standard (pay per I/O) or I/O-Optimized (included)	Included in storage (gp3) or provisioned (io1/io2)
Max Connections	Higher (optimized connection handling)	Based on instance memory
Engines	MySQL-compatible, PostgreSQL-compatible only	MySQL, PostgreSQL, MariaDB, Oracle, SQL Server

When to Choose Aurora

High availability is critical – built-in 6-way replication across 3 AZs, <30s failover.
Read-heavy workloads – up to 15 read replicas with millisecond replication lag.
Variable workloads – Aurora Serverless v2 scales compute automatically (even to zero).

Global applications – Aurora Global Database provides <1 second cross-region replication.
Development/testing – fast cloning creates copies in seconds without additional storage cost.
Need to undo mistakes quickly – Backtrack rewinds the database without restoring from backup.

When to Choose RDS

Cost-sensitive workloads – 20-30% cheaper for equivalent instance sizes.
Non-MySQL/PostgreSQL engines – need Oracle, SQL Server, or MariaDB.
Simple workloads – don’t need Aurora’s advanced features (global DB, serverless, cloning).
Lift-and-shift migrations – exact MySQL/PostgreSQL compatibility without Aurora-specific behavior.
Predictable I/O costs – gp3 storage includes I/O in the storage price.

AWS Certification Exam Practice Questions

A company needs a database that automatically scales storage and provides sub-second failover with no data loss. Which service meets these requirements?
1. RDS MySQL with Multi-AZ
2. Amazon Aurora
3. RDS PostgreSQL with read replicas
4. DynamoDB

A developer accidentally ran a DELETE query on a production Aurora MySQL database 5 minutes ago. What is the fastest recovery method?
1. Restore from automated backup
2. Point-in-time recovery
3. Aurora Backtrack
4. Promote a read replica
A global application needs a relational database with cross-region read access and less than 1 second replication lag for disaster recovery. Which solution is appropriate?
1. RDS with cross-region read replicas
2. Aurora Global Database
3. DynamoDB Global Tables
4. RDS Multi-AZ with manual failover
A startup has unpredictable traffic – sometimes zero users, sometimes thousands. They need a relational database that scales to zero during idle periods to minimize costs. What should they use?
1. RDS with Scheduled Scaling
2. Aurora Provisioned with Auto Scaling
3. Aurora Serverless v2
4. DynamoDB On-Demand