Question 812 of 1,040
Design Secure ArchitecturesmediumMultiple ChoiceObjective-mapped

SAA-C03 Design Secure Architectures Practice Question

This SAA-C03 practice question tests your understanding of design secure architectures. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

An e-commerce application uses Aurora MySQL. Writes are modest, but the product-detail page generates many read-only queries and the writer instance CPU is high. The application can tolerate a small amount of replication lag on those reads. What should the team do?

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Add Aurora read replicas and send read-only traffic to the reader endpoint.

Adding Aurora read replicas and directing read-only traffic to the reader endpoint offloads SELECT queries from the writer instance, reducing its CPU load. Aurora replicas share the same underlying storage volume, so replication lag is minimal (typically <100ms) and acceptable for the product-detail page. This scales read throughput without increasing writer instance size or cost.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Add Aurora read replicas and send read-only traffic to the reader endpoint.

    Why this is correct

    Aurora read replicas are the right way to scale read-heavy workloads and reduce pressure on the writer instance. By directing read-only traffic to the reader endpoint, the application can offload product-page queries while keeping writes on the primary instance. Because a small amount of replication lag is acceptable, this approach aligns well with the workload's consistency and performance needs.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Increase the writer instance size and keep all traffic on the primary.

    Why it's wrong here

    A larger writer may temporarily relieve CPU pressure, but it does not solve the architectural issue of read traffic competing with writes. The application would still send every query to the primary instance, limiting future scalability. Since the reads can tolerate a bit of lag, offloading them to replicas is a better design.

    When this WOULD be correct

    If the application cannot tolerate any replication lag and all queries must be strongly consistent, or if the read workload is already low and the bottleneck is write performance, then increasing the writer instance size would be correct.

  • Replace Aurora with DynamoDB to eliminate replication lag.

    Why it's wrong here

    Switching database engines would require major application redesign and is not the simplest answer to a read-scaling problem in Aurora. DynamoDB has different query patterns, data modeling rules, and consistency behavior. The question asks how to improve the current Aurora architecture, so a full migration is unnecessary and too disruptive.

    When this WOULD be correct

    A question where the application requires a fully managed NoSQL database with single-digit millisecond latency at any scale, and the data model is key-value or document-based, with no need for complex joins or transactions. For example: 'A gaming leaderboard needs to store player scores and retrieve top players with low latency; the data is simple and does not require relational queries.'

  • Enable Multi-AZ failover only, because it increases read throughput automatically.

    Why it's wrong here

    Multi-AZ improves availability and failover behavior, but it is not a read-scaling feature. It ensures that the database can recover quickly if the primary fails, yet it does not automatically redirect large volumes of read traffic away from the writer for performance purposes. The problem here is read load, not just availability.

    When this WOULD be correct

    A question where the primary concern is database availability during an AZ outage, and read scaling is not required. For example: 'An application needs automatic failover to a standby instance in another AZ with zero data loss. What should be enabled?'

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.

Add Aurora read replicas and send read-only traffic to the reader endpoint.Correct answer

Why this is correct

Aurora read replicas are the right way to scale read-heavy workloads and reduce pressure on the writer instance. By directing read-only traffic to the reader endpoint, the application can offload product-page queries while keeping writes on the primary instance. Because a small amount of replication lag is acceptable, this approach aligns well with the workload's consistency and performance needs.

Increase the writer instance size and keep all traffic on the primary.Wrong answer — click to see why

Why this is wrong here

Increasing the writer instance size does not offload read traffic from the primary node, so CPU remains high from read queries. The question explicitly allows replication lag, making read replicas a more cost-effective and scalable solution.

★ When this WOULD be the correct answer

If the application cannot tolerate any replication lag and all queries must be strongly consistent, or if the read workload is already low and the bottleneck is write performance, then increasing the writer instance size would be correct.

Why candidates choose this

Candidates may think that a larger instance handles more throughput overall, overlooking that read replicas can distribute read load without scaling the writer.

Replace Aurora with DynamoDB to eliminate replication lag.Wrong answer — click to see why

Why this is wrong here

DynamoDB is a NoSQL database that does not support the same relational query patterns as Aurora MySQL, and the application would require significant refactoring. Additionally, DynamoDB does not inherently eliminate replication lag; it uses eventually consistent reads by default, which can have lag.

★ When this WOULD be the correct answer

A question where the application requires a fully managed NoSQL database with single-digit millisecond latency at any scale, and the data model is key-value or document-based, with no need for complex joins or transactions. For example: 'A gaming leaderboard needs to store player scores and retrieve top players with low latency; the data is simple and does not require relational queries.'

Why candidates choose this

Candidates may think DynamoDB is always faster and has no replication lag, overlooking the fact that it uses eventually consistent reads and requires application changes to adapt to a different data model.

Enable Multi-AZ failover only, because it increases read throughput automatically.Wrong answer — click to see why

Why this is wrong here

Multi-AZ failover provides high availability but does not increase read throughput; the standby replica cannot serve reads, so it does not offload the writer instance's CPU.

★ When this WOULD be the correct answer

A question where the primary concern is database availability during an AZ outage, and read scaling is not required. For example: 'An application needs automatic failover to a standby instance in another AZ with zero data loss. What should be enabled?'

Why candidates choose this

Candidates may confuse Multi-AZ with read replicas, thinking the standby can handle read traffic, or assume that failover automatically improves performance.

Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is confusing Multi-AZ (which only provides failover) with read replicas (which offload reads), leading candidates to pick Option D thinking it improves read performance.

Detailed technical explanation

How to think about this question

Aurora read replicas (up to 15) connect to the same cluster volume and serve reads with sub-second lag; the reader endpoint load-balances across all replicas automatically. Under the hood, Aurora uses a distributed storage system where the writer commits redo logs, and replicas apply them asynchronously, ensuring consistency without full data copies. In practice, for a product-detail page that tolerates eventual consistency, this pattern can reduce writer CPU from 90% to under 30% with just two replicas.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this SAA-C03 question test?

Design Secure Architectures — This question tests Design Secure Architectures — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Add Aurora read replicas and send read-only traffic to the reader endpoint. — Adding Aurora read replicas and directing read-only traffic to the reader endpoint offloads SELECT queries from the writer instance, reducing its CPU load. Aurora replicas share the same underlying storage volume, so replication lag is minimal (typically <100ms) and acceptable for the product-detail page. This scales read throughput without increasing writer instance size or cost.

What should I do if I get this SAA-C03 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This SAA-C03 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAA-C03 exam.