SAA-C03 Design Cost-Optimized Architectures Practice Question

A test environment has EC2 instances that are oversized based on CPU, memory, and network utilisation. Which AWS service should identify rightsizing recommendations? The architecture review board prefers a managed AWS-native control.

⚠ Common exam trap

Candidates often confuse AWS Compute Optimizer with other monitoring or cost tools (like AWS Trusted Advisor or Cost Explorer), but the question specifically asks for a managed AWS-native service that identifies rightsizing recommendations, which is Compute Optimizer's primary function.

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 is a managed service that uses machine learning to analyze historical utilization metrics (CPU, memory, network, and storage) and provides rightsizing recommendations for EC2 instances. It identifies over-provisioned resources and suggests instance types that better match workload requirements, directly addressing the oversized EC2 instances in the test environment.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

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AWS DataSync
Why it's wrong here
AWS DataSync is a data-transfer service used to move large files between on-premises storage and AWS, not a recommendation engine. It never reads EC2 instance utilization metrics and cannot suggest that an instance is oversized or undersized. Therefore it cannot help rightsize the test environment's EC2 resources.
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AWS Shield
Why it's wrong here
AWS Shield is a managed DDoS protection service, and its focus is on network and transport layer attack mitigation. It does not collect compute-level metrics such as CPU, memory, or I/O, so it has no mechanism to judge whether an EC2 instance is oversized. Choosing Shield would address security, not cost optimization.
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AWS Artifact
Why it's wrong here
AWS Artifact is a self-service portal for accessing AWS compliance reports, SOC/ISO certifications, and agreements like the Business Associate Addendum. It is a documentation repository rather than an analytics or resource-sizing tool, so it offers no EC2 usage observations or rightsizing recommendations. It is therefore unrelated to determining oversized instances.
✓
AWS Compute Optimizer
Why this is correct
AWS Compute Optimizer uses machine learning to analyze historical utilization metrics from CloudWatch, including CPU, memory, network, and storage, to identify whether EC2 instances are oversized, undersized, or optimally sized. It then produces instance type recommendations with a performance risk score, directly answering the question of whether the test environment's instances are oversized. Its findings are actionable, enabling cost savings without sacrificing workload performance.

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

Go deeper

SAA-C03 Design Cost-Optimized Architectures Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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