SAA-C03 Design Cost-Optimized Architectures Practice Question

An S3 bucket stores application logs. After 30 days, the team rarely accesses the logs, but compliance requires keeping them for 18 months. Which setup most directly reduces storage cost while maintaining compliance?

⚠ Common exam trap

A common mix-up: candidates think moving to a different region or using versioning reduces costs, but the core concept is that S3 Lifecycle policies directly automate cost optimization by transitioning to colder storage classes and expiring data, which is the most direct and compliant approach.

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

✓

Configure an S3 Lifecycle policy to transition objects to a colder storage class after 30 days and expire (delete) them after 18 months.

S3 Lifecycle policies allow you to automatically transition objects to cheaper storage classes (e.g., S3 Standard-IA or S3 Glacier Deep Archive) after 30 days, reducing storage costs for rarely accessed logs. The policy also sets an expiration action to delete objects after 18 months, meeting the compliance requirement without manual intervention.

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 an S3 Lifecycle policy to transition objects to a colder storage class after 30 days and expire (delete) them after 18 months.
Why this is correct
This lifecycle policy is the right approach because it automatically transitions 30-day-old log objects to a lower-cost storage class — such as S3 Standard-IA or S3 Glacier Instant Retrieval — which directly matches the noted shift in access pattern after the first 30 days. The separate expiration action after 18 months enforces the compliance requirement to retain logs for exactly that period and then delete them, preventing both premature deletion and runaway storage growth. Lifecycle transitions are managed by S3, so the team does not need custom code to move or expire objects.
✗
Enable S3 Versioning and rely on deleting old versions after 30 days to reduce storage costs while keeping the latest data.
Why it's wrong here
Versioning changes how objects are stored but does not inherently implement a deterministic “keep for 18 months” retention rule for all log data. You could still violate compliance if deletes/version retention are not aligned with the required retention window.
✗
Move the bucket to a different AWS region farther from the users to reduce the likelihood of accidental reads and thereby lower storage costs.
Why it's wrong here
Moving the bucket to a different region does not reduce S3 storage cost for the data itself; pricing is region-specific and not based on distance from users. Cross-region data transfer and potential replication fees would increase total expenses, and a distant region could have a higher per-GB rate. Critically, changing regions does nothing to automate the required 18-month retention or deletion of log objects, leaving the compliance requirement unaddressed.
✗
Switch all objects to S3 Glacier Instant Retrieval immediately, regardless of object age, to minimize storage charges.
Why it's wrong here
Applying Glacier Instant Retrieval to all objects immediately ignores the noted 30-day active-access period; that storage class is designed for infrequently accessed data and carries per-request retrieval fees plus a 90-day minimum storage duration that would make short-lived recent logs more costly than S3 Standard. The option also lacks an expiration action, so it does not enforce the 18-month retention and deletion requirement. A lifecycle policy that transitions by age and expires after 18 months is the correct application of cold storage.

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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