Question 1,672 of 1,746
Continuous Improvement for Existing SolutionsmediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is to enable Cluster Mode on the ElastiCache for Redis cluster and configure Multi-AZ. This combination shards session data across multiple nodes while replicating each shard to a different Availability Zone, so if one AZ fails, the replicas in another AZ automatically take over without data loss. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this scenario tests your understanding of stateful application resilience within Auto Scaling groups, where the common trap is confusing vertical scaling (larger instances) with horizontal fault tolerance or mistaking Memcached’s lack of replication for Redis’s durability. Remember that Cluster Mode provides both sharding and automatic failover across AZs, while Multi-AZ ensures the replicas are physically separated. A quick memory tip: “Cluster for sharding, Multi-AZ for survival” — without both, a single AZ failure wipes out your session data.

SAP-C02 Continuous Improvement for Existing Solutions Practice Question

This SAP-C02 practice question tests your understanding of continuous improvement for existing solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 running a stateful web application on Amazon EC2 instances in an Auto Scaling group. The instances store session data in an Amazon ElastiCache for Redis cluster. The company wants to improve the application's fault tolerance and ensure that session data is not lost if an Availability Zone fails. What should the solutions architect do?

Question 1mediummultiple choice
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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

Enable Cluster Mode on the ElastiCache for Redis cluster and configure Multi-AZ.

Option B is correct because ElastiCache for Redis with Cluster Mode enabled automatically shards data across multiple nodes and provides Multi-AZ with automatic failover, ensuring high availability and data durability. Option A is wrong because increasing instance size does not protect against AZ failure. Option C is wrong because a single-node cluster has no replication; if the node fails, data is lost. Option D is wrong because ElastiCache for Memcached does not support persistence or replication; data loss occurs on node failure.

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.

  • Enable Cluster Mode on the ElastiCache for Redis cluster and configure Multi-AZ.

    Why this is correct

    Cluster Mode with Multi-AZ provides replication and automatic failover across AZs, protecting against AZ failure.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Configure the ElastiCache for Redis cluster to have multiple read replicas in the same region.

    Why it's wrong here

    Read replicas help with read scaling but if the primary fails in an AZ outage, you still need automatic failover; Multi-AZ is required.

  • Increase the instance size of the EC2 instances to handle more load.

    Why it's wrong here

    Instance size does not affect session data durability; it only improves compute capacity.

  • Migrate from ElastiCache for Redis to ElastiCache for Memcached.

    Why it's wrong here

    Memcached does not support persistence or replication; data loss is more likely.

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

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

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.

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FAQ

Questions learners often ask

What does this SAP-C02 question test?

Continuous Improvement for Existing Solutions — This question tests Continuous Improvement for Existing Solutions — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Enable Cluster Mode on the ElastiCache for Redis cluster and configure Multi-AZ. — Option B is correct because ElastiCache for Redis with Cluster Mode enabled automatically shards data across multiple nodes and provides Multi-AZ with automatic failover, ensuring high availability and data durability. Option A is wrong because increasing instance size does not protect against AZ failure. Option C is wrong because a single-node cluster has no replication; if the node fails, data is lost. Option D is wrong because ElastiCache for Memcached does not support persistence or replication; data loss occurs on node failure.

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.

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Last reviewed: Jun 20, 2026

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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.