SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application stores session state in an Amazon ElastiCache for Redis cluster. Recently, the operations team noticed that during traffic spikes, the ALB returns 5xx errors and the application becomes slow. CloudWatch metrics show that the Redis cluster's CPU utilization reaches 100% and memory usage is high. The Auto Scaling group scales out, but the new instances take several minutes to warm up and become healthy. The company needs to improve the application's ability to handle traffic spikes with minimal impact on performance. Which solution should the company implement?
⚠ Common exam trap
A common mix-up: candidates confuse vertical scaling (increasing instance size) with horizontal scaling (adding shards), and fail to recognize that cluster mode is the only option that distributes both CPU and memory load across multiple nodes, which is necessary when a single node reaches 100% CPU utilization.
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 for the Redis cluster and add more shards.
Enabling cluster mode for the Redis cluster and adding more shards horizontally partitions the data across multiple nodes, distributing both CPU and memory load. This directly addresses the 100% CPU and high memory utilization during traffic spikes, allowing the cluster to handle more concurrent requests without performance degradation. Cluster mode also provides linear scalability, which is essential for a critical web application experiencing variable traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure ElastiCache Auto Scaling to automatically add nodes when CPU utilization exceeds 75%.
Why it's wrong here
ElastiCache does not support automatic scaling based on CPU; scaling is manual.
- ✓
Enable cluster mode for the Redis cluster and add more shards.
Why this is correct
Cluster mode distributes data and load across multiple shards, increasing CPU and memory capacity.
- ✗
Enable Multi-AZ replication for the Redis cluster.
Why it's wrong here
Multi-AZ provides high availability but does not increase capacity.
- ✗
Increase the instance size of the Redis cluster to a larger node type.
Why it's wrong here
Vertical scaling is limited and may not handle extreme spikes as well as horizontal scaling.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.