SAA-C03 Design Cost-Optimized Architectures Practice Question
A team stores application logs in Amazon S3. They need access to the logs only occasionally for troubleshooting (infrequent access), and they want to reduce storage cost automatically over time without manually moving objects. What should they implement?
⚠ Common exam trap
A common mix-up: candidates confuse lifecycle policies with deletion policies, thinking that deleting objects after a short period (Option B) is a valid cost-saving strategy, but the question explicitly requires retaining logs for occasional troubleshooting, so deletion is not appropriate.
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
✓
An S3 lifecycle policy that transitions objects to a lower-cost storage class after a set number of days
An S3 lifecycle policy can automatically transition objects from S3 Standard to lower-cost storage classes (e.g., S3 Standard-IA, S3 One Zone-IA, or S3 Glacier Instant Retrieval) after a specified number of days. This meets the requirement of reducing storage costs over time for infrequently accessed logs without manual intervention, as the policy automates the movement based on object age.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
An S3 lifecycle policy that transitions objects to a lower-cost storage class after a set number of days
Why this is correct
S3 lifecycle policies can automatically transition objects based on age to storage classes priced for infrequent access (for example, Standard-IA or Glacier-based classes). This preserves the data for later troubleshooting while lowering storage cost as objects become older.
- ✗
An S3 lifecycle policy that deletes objects after 1 day to eliminate storage costs
Why it's wrong here
Deleting after 1 day would remove data before it can be used for occasional troubleshooting. Storage cost optimization must still respect retention and troubleshooting requirements; lifecycle rules should transition to cheaper classes rather than delete immediately unless deletion is explicitly acceptable.
When this WOULD be correct
An S3 lifecycle policy that deletes objects after a set number of days would be correct if the requirement is to automatically remove logs after a retention period (e.g., compliance mandates deletion after 90 days) and no longer-term access is needed.
- ✗
An S3 lifecycle policy that keeps all objects in S3 Standard and only applies compression at read time
Why it's wrong here
Staying in S3 Standard does not address the cost driver (storage class pricing based on access frequency). “Compression at read time” is not an S3 lifecycle storage class optimization mechanism and would not directly lower S3 storage class charges as requested.
When this WOULD be correct
An S3 Lifecycle policy that keeps all objects in S3 Standard and applies compression at read time would be correct if the question asked for a solution to reduce data transfer costs or improve read performance for frequently accessed logs, while maintaining immediate access without storage class transitions.
- ✗
A policy that changes bucket encryption from SSE-S3 to SSE-KMS to reduce storage cost
Why it's wrong here
Switching from SSE-S3 to SSE-KMS will not lower S3 storage costs; in fact, it typically increases them because AWS KMS incurs per-request charges for encrypt and decrypt operations and a monthly key fee. S3 storage class pricing is determined by the amount of data stored and the access/retrieval rates, not by the encryption mechanism. Since the logs are infrequently accessed, the correct approach is to transition objects into a cheaper storage class via lifecycle rules, not to change encryption to a costlier KMS option.
When this WOULD be correct
A question where the requirement is to enforce customer-managed encryption keys for compliance or to control key rotation, and cost is not the primary concern.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.
✓An S3 lifecycle policy that transitions objects to a lower-cost storage class after a set number of daysCorrect answer▾
Why this is correct
S3 lifecycle policies can automatically transition objects based on age to storage classes priced for infrequent access (for example, Standard-IA or Glacier-based classes). This preserves the data for later troubleshooting while lowering storage cost as objects become older.
✗An S3 lifecycle policy that deletes objects after 1 day to eliminate storage costsWrong answer — click to see why▾
Why this is wrong here
Deleting logs after 1 day prevents troubleshooting access for incidents that may occur later, and the requirement is to reduce cost automatically over time, not eliminate data immediately.
★ When this WOULD be the correct answer
An S3 lifecycle policy that deletes objects after a set number of days would be correct if the requirement is to automatically remove logs after a retention period (e.g., compliance mandates deletion after 90 days) and no longer-term access is needed.
Why candidates choose this
Candidates may think deleting old logs is the simplest way to reduce cost, overlooking the need for occasional troubleshooting access and the availability of lower-cost storage classes.
✗An S3 lifecycle policy that keeps all objects in S3 Standard and only applies compression at read timeWrong answer — click to see why▾
Why this is wrong here
S3 Lifecycle policies cannot apply compression at read time; they only transition or expire objects. Compression at read time is not a storage cost reduction feature and would not automatically reduce costs over time.
★ When this WOULD be the correct answer
An S3 Lifecycle policy that keeps all objects in S3 Standard and applies compression at read time would be correct if the question asked for a solution to reduce data transfer costs or improve read performance for frequently accessed logs, while maintaining immediate access without storage class transitions.
Why candidates choose this
Candidates may think compression reduces storage costs, but S3 does not support server-side compression at read time, and the option incorrectly implies that compression can be applied automatically via a lifecycle policy.
✗A policy that changes bucket encryption from SSE-S3 to SSE-KMS to reduce storage costWrong answer — click to see why▾
Why this is wrong here
Changing encryption from SSE-S3 to SSE-KMS does not reduce storage cost; in fact, SSE-KMS incurs additional KMS key usage charges, increasing cost.
★ When this WOULD be the correct answer
A question where the requirement is to enforce customer-managed encryption keys for compliance or to control key rotation, and cost is not the primary concern.
Why candidates choose this
Candidates may mistakenly believe that using a more advanced encryption method like KMS reduces storage costs, or they confuse encryption cost with storage cost.
Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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
Related to this question
About these practice questions
One of 935 original SAA-C03 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.