SAA-C03 Design Cost-Optimized Architectures Practice Question
A marketing site has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations?
⚠ Common exam trap
Candidates often confuse AWS Compute Optimizer with AWS Trusted Advisor, which also provides cost optimization checks but does not offer the same ML-driven, granular rightsizing recommendations for EC2 instances.
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
✓
AWS Compute Optimizer
AWS Compute Optimizer analyzes historical utilization metrics (CPU, memory, network, and storage) from CloudWatch and uses machine learning to identify over-provisioned or under-provisioned EC2 instances. It generates actionable rightsizing recommendations, including instance type changes, to optimize cost and performance. This directly addresses the scenario of oversized EC2 instances.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
AWS Shield
Why it's wrong here
AWS Shield provides DDoS protection at the network and transport layers; it does not collect or analyse EC2 CPU, memory, or network metrics, so it cannot generate rightsizing recommendations. It is tempting because Shield also operates on EC2-adjacent infrastructure, but it would be the correct choice only when defending a workload against volumetric denial-of-service attacks.
- ✓
AWS Compute Optimizer
Why this is correct
AWS Compute Optimizer analyses CloudWatch metrics from EC2 instances to generate rightsizing recommendations, flagging over-provisioned CPU, memory and network capacity. It directly satisfies the stem's requirement to identify oversized instances, unlike Trusted Advisor's narrower checks or Cost Explorer's spend-only view.
- ✗
AWS DataSync
Why it's wrong here
AWS DataSync migrates and replicates file data between on-premises storage, Amazon S3, EFS and FSx; it gathers no compute metrics and cannot analyse EC2 utilisation. It is tempting because it also targets AWS resources, but it would be the right choice for moving large datasets into AWS, not for producing rightsizing recommendations.
- ✗
AWS Artifact
Why it's wrong here
AWS Artifact supplies compliance reports and agreements, such as SOC and ISO attestations, so it holds no utilisation metrics and cannot produce rightsizing recommendations. It is tempting because it centralises audit evidence for governance reviews, and would be the right choice when a team needs on-demand access to AWS security and compliance documentation.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAA-C03 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 SAA-C03 exam.