hardMultiple ChoiceObjective-mapped
CV0-004 Practice Question: A company runs an e-commerce platform on a public…
A company runs an e-commerce platform on a public cloud. The architecture consists of a front-end load balancer, a web server tier, and an RDS database. The web servers are in an auto-scaling group across two availability zones. The database is a single Multi-AZ deployment. After a recent traffic surge, the web servers scaled but the database CPU utilization reached 90%, causing slow page loads. The database is a db.r5.large instance with 16 GB RAM and 2 vCPUs. The company expects double the traffic during the upcoming holiday season. The budget is limited. Which action should the cloud architect take to address the database bottleneck while minimizing cost?
⚠ Common exam trap
CompTIA often tests the misconception that upgrading instance size is the simplest fix, but the trap here is that horizontal scaling with read replicas is more cost-effective and elastic for read-heavy workloads than vertical scaling, especially when budget is limited.
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 read replicas of the database and configure the application to use them for read queries; implement auto-scaling for read replicas based on average CPU utilization
Adding read replicas offloads read queries from the primary database, reducing CPU utilization. Auto-scaling read replicas based on average CPU utilization ensures cost efficiency by scaling only when needed, which aligns with the limited budget and expected traffic surge. This approach directly addresses the bottleneck without requiring a costly instance upgrade or complex sharding.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement a fully managed caching layer, such as ElastiCache, in front of the database
Why it's wrong here
Caching reduces read load but adds cost and complexity; read replicas are more direct and cost-efficient for read-heavy workloads.
- ✓
Add read replicas of the database and configure the application to use them for read queries; implement auto-scaling for read replicas based on average CPU utilization
Why this is correct
Read replicas distribute read traffic, reducing primary CPU load, and auto-scaling ensures cost efficiency.
- ✗
Separate the database into multiple smaller databases using sharding
Why it's wrong here
Sharding adds significant complexity and is not typically needed for read-heavy scaling; it's for write scaling.
- ✗
Upgrade the database to a larger instance type, such as db.r5.2xlarge
Why it's wrong here
Vertical scaling is expensive and may not be necessary if read replicas can offload reads.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.