Service Comparison
RDS vs Aurora vs DynamoDB
The main split is relational SQL versus key-value/document access patterns.
What They Have in Common
Each option can solve part of the scenario. The exam expects you to choose the one that satisfies the stated constraints with the right operational burden, security boundary, availability model, and cost behavior.
Key Differences
| Option | Primary model | Best use | Security | Availability | Operations and cost |
|---|---|---|---|---|---|
| RDS | Managed standard relational engines | Engine compatibility, transactions, SQL, existing apps | Private subnets, SGs, KMS, Secrets Manager | Multi-AZ optional; read replicas optional | Instance, storage, I/O, license cost |
| Aurora | AWS relational database engine | High-performance MySQL/PostgreSQL-compatible workloads | Same relational controls plus Aurora-specific features | Replicated storage and fast failover options | Capacity mode and I/O model matter |
| DynamoDB | Serverless NoSQL | Known key-value access at massive scale | IAM, KMS, endpoint policies, fine-grained controls | Regional HA; global tables optional | Read/write mode, indexes, streams, storage |
Typical Exam Clues
Practice After Studying
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Sources and Review Metadata
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