The answer is Amazon ElastiCache for Redis, as it provides a managed, scalable low-latency key-value store for session state that integrates seamlessly with EC2 instances in an Auto Scaling group. Redis stores session data entirely in-memory, delivering sub-millisecond response times, while ElastiCache handles replication, failover, and scaling without operational overhead. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this scenario tests your ability to distinguish between purpose-built databases: DynamoDB is a valid alternative but incurs higher costs for simple session data due to its provisioned throughput and storage overhead, whereas RDS is relational and local instance store lacks durability. A common trap is choosing DynamoDB for its “serverless” appeal, but for session state, Redis is both more cost-effective and simpler to implement. Memory tip: “Session state screams for Redis in-memory streams.”
SAP-C02 Design for New Solutions Practice Question
This SAP-C02 practice question tests your understanding of design for new solutions. 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.
A company is designing a new web application that requires a scalable, low-latency key-value store for session state. The application runs on EC2 instances in an Auto Scaling group. Which solution is the MOST cost-effective and scalable?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use Amazon ElastiCache for Redis.
ElastiCache for Redis (option B) is a managed, scalable, low-latency key-value store ideal for session state. Option A (DynamoDB) works but is more expensive for simple session data. Option C (RDS) is relational and not low-latency for key-value. Option D (local instance store) is not durable.
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.
✗
Store session state on the local instance store of each EC2 instance.
Why it's wrong here
Not durable and lost on instance termination.
✓
Use Amazon ElastiCache for Redis.
Why this is correct
ElastiCache Redis is optimized for low-latency key-value storage and is cost-effective.
Related concept
Read the scenario before looking for a memorised answer.
✗
Store session state in Amazon DynamoDB.
Why it's wrong here
DynamoDB is a good option but less cost-effective for simple session data than ElastiCache.
✗
Store session state in Amazon RDS for MySQL.
Why it's wrong here
RDS is not a key-value store and has higher latency.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 SAP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Design for New Solutions — This question tests Design for New Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use Amazon ElastiCache for Redis. — ElastiCache for Redis (option B) is a managed, scalable, low-latency key-value store ideal for session state. Option A (DynamoDB) works but is more expensive for simple session data. Option C (RDS) is relational and not low-latency for key-value. Option D (local instance store) is not durable.
What should I do if I get this SAP-C02 question wrong?
Identify which SAP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This SAP-C02 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 SAP-C02 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.