Cost-Optimized Variable Relational Database on AWS

SAA-C03 By islever Editorial Last updated

Design cost-optimized database solutions.

Short answer

B Deploy the database on Amazon Aurora Serverless to automatically scale the database capacity based on actual usage to accommodate the workload.

Question

A company is developing a new application that uses a relational database to store user data and application configurations. The company expects the application to have steady user growth. The company expects the database usage to be variable and read-heavy, with occasional writes. The company wants to cost-optimize the database solution. The company wants to use an AWS managed database solution that will provide the necessary performance. Which solution will meet these requirements MOST cost-effectively?
  1. Deploy the database on Amazon RDS. Use Provisioned IOPS SSD storage to ensure consistent performance for read and write operations.
  2. Deploy the database on Amazon Aurora Serverless to automatically scale the database capacity based on actual usage to accommodate the workload. Correct Answer
  3. Deploy the database on Amazon DynamoDB. Use on-demand capacity mode to automatically scale throughput to accommodate the workload.
  4. Deploy the database on Amazon RDS. Use magnetic storage and use read replicas to accommodate the workload.

Key Takeaways

The question tests the ability to match database engine types with workload characteristics while optimizing for cost; the common trap is choosing high-performance fixed resources or non-relational databases.

Amazon Aurora Serverless is the most cost-effective solution for variable, read-heavy relational workloads. This page explains why it outperforms Provisioned IOPS and DynamoDB for this specific scenario.

Common mistake: Candidates often choose Option A (RDS with Provisioned IOPS) because they prioritize performance over cost, failing to recognize that paying for unused capacity is inefficient for variable traffic.

Expert Analysis

Why the Answer Is Correct

Option B is the correct answer because Amazon Aurora Serverless automatically scales compute capacity based on actual usage, which aligns perfectly with a 'variable' workload. It uses SSD storage, ensuring high performance for the 'read-heavy' nature of the application without the need to provision excess capacity in advance. This pay-per-use model provides the best cost optimization for unpredictable traffic patterns.

Why the Other Options Are Wrong

Option A (RDS with Provisioned IOPS) is incorrect because you must pre-provision IOPS, leading to wasted costs during low-usage periods. Option C (DynamoDB) is invalid because the requirement specifies a 'relational database,' and DynamoDB is a NoSQL key-value store. Option D (RDS with magnetic storage) is obsolete and performs poorly compared to SSDs, making it unsuitable for modern performance requirements.

Community Comment Notes

Community consensus strongly supports Option B. As LeonSauveterre noted, "You only pay for the database capacity you use, making it cost-efficient for unpredictable traffic." AMEJack correctly pointed out that Aurora relies on SSDs, eliminating Option D due to outdated technology. The comments highlight the importance of matching the database type (Relational vs. NoSQL) first, then selecting the deployment model (Serverless vs. Provisioned).

Exam Strategy

Always identify the database engine type constraint first (e.g., Relational vs. NoSQL). Then, evaluate the deployment model (Provisioned vs. Serverless) against the traffic pattern (Steady vs. Variable) to determine the most cost-effective option.

Frequently Asked Questions

Why is DynamoDB not suitable here?

The question explicitly requires a 'relational database.' DynamoDB is a NoSQL key-value store, so it does not meet the fundamental architectural requirement.

Can RDS with Provisioned IOPS be cost-optimized?

No. Provisioned IOPS requires you to reserve and pay for a specific amount of I/O capacity regardless of actual usage, which is inefficient for variable traffic.

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Community Votes

B
100%

100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 3 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 3

  1. LeonSauveterre 👍 2 Answered B
    A - You’d pay for high performance even when you don’t need it B - You only pay for the database capacity you use, making it cost-efficient for unpredictable traffic. C - DynamoDB is not even a relational database. D - Magnetic disks have significantly slower IOPS compared to SSDs. P.S. In the AWS context, magnetic storage refers to standard storage volumes (previously called "Magnetic" volumes) in EBS. It offers lower performance compared to modern SSD storage but is cheaper per GB.
  2. AMEJack 👍 2 Answered B
    Option D is out: Aurora data is stored in the cluster volume, which is a single, virtual volume that uses solid state drives (SSDs). So option B is correct
  3. dhewa 👍 3 Answered B
    B is my choice.

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