The correct answer is to enable cluster mode and distribute the cache across multiple shards. This directly addresses the root cause: a single-node ElastiCache Redis instance hitting a CPU ceiling under load, which forces evictions and lowers the cache hit ratio. By enabling cluster mode, data is partitioned across multiple primary shards, each handling a fraction of the keyspace and CPU demand, which improves both throughput and hit ratio. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this scenario tests your understanding of scaling strategies beyond vertical scaling—a common trap is choosing a larger instance size, which only delays the bottleneck without fixing the sharding architecture. Remember the mnemonic “Shard to guard the CPU card” to recall that cluster mode distributes load horizontally, not vertically.
SAP-C02 Continuous Improvement for Existing Solutions Practice Question
This SAP-C02 practice question tests your understanding of continuous improvement for existing solutions. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 uses Amazon ElastiCache for Redis to cache frequently accessed data. The cache cluster is a single node (cache.r5.large). Over time, the cache hit ratio has decreased, and the CPU utilization is consistently above 80%. What should a solutions architect do to improve performance?
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 and distribute the cache across multiple shards.
Option D is correct because moving to a cluster mode enabled configuration distributes data across multiple shards, reducing CPU load and improving hit ratio. Option A is wrong because simply increasing instance size may help temporarily but doesn't address architectural issues. Option B is wrong because read replicas are for read scaling, not reducing CPU on the primary. Option C is wrong because TTL reduction may increase misses.
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.
✗
Reduce the Time-to-Live (TTL) of cached objects.
Why it's wrong here
Reducing TTL increases cache misses, worsening the hit ratio.
✗
Add a read replica to offload read traffic.
Why it's wrong here
Read replicas do not reduce CPU on the primary for write-heavy workloads.
✗
Scale up to a larger node type, such as cache.r5.xlarge.
Why it's wrong here
Scaling up may not be cost-effective and doesn't leverage distributed processing.
✓
Enable cluster mode and distribute the cache across multiple shards.
Why this is correct
Cluster mode allows horizontal scaling and reduces CPU pressure.
Related concept
Read the scenario before looking for a memorised answer.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
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 and distribute the cache across multiple shards. — Option D is correct because moving to a cluster mode enabled configuration distributes data across multiple shards, reducing CPU load and improving hit ratio. Option A is wrong because simply increasing instance size may help temporarily but doesn't address architectural issues. Option B is wrong because read replicas are for read scaling, not reducing CPU on the primary. Option C is wrong because TTL reduction may increase misses.
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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Question Discussion
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