The answer is to use S3 Standard for 30 days, then transition to S3 Standard-IA, and finally to S3 Glacier Deep Archive after 90 days. This is the most cost-effective strategy because it aligns the S3 lifecycle policy optimization for data lake storage directly with the access pattern: frequent access for the first month, rare access thereafter, and a seven-year compliance hold. By moving data through progressively cheaper tiers—Standard for active use, Standard-IA for a short buffer period with lower storage cost, and Deep Archive for the long-term retention—you minimize total cost while meeting the retention requirement. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of lifecycle transitions and the trade-off between retrieval costs and storage savings; a common trap is jumping straight to Glacier or skipping Standard-IA, which would incur unnecessary retrieval fees for data still accessed occasionally. Memory tip: think “30-90-7” — 30 days Standard, 90 days to Deep Archive, 7 years total retention.
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A data engineer is designing a data lake on Amazon S3. The data is accessed frequently for the first 30 days, then rarely after that. Compliance requires that data be retained for 7 years. What is the MOST cost-effective storage strategy?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use S3 Standard for 30 days, then transition to S3 Standard-IA, then to S3 Glacier Deep Archive after 90 days.
Option D is the most cost-effective because it matches the access pattern: S3 Standard for the first 30 days of frequent access, then S3 Standard-IA for the next 60 days (reduced storage cost with a retrieval fee), and finally S3 Glacier Deep Archive for the remaining ~6.9 years to meet the 7-year retention requirement at the lowest possible storage cost. This lifecycle policy minimizes total cost by transitioning data to progressively cheaper storage tiers as access frequency drops, while still meeting compliance.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use S3 Intelligent-Tiering for the entire 7 years.
Why it's wrong here
Intelligent-Tiering has monitoring and automation costs that may not be optimal.
✗
Store all data in S3 Standard for 7 years.
Why it's wrong here
Standard is expensive for data accessed rarely after 30 days.
✗
Use S3 Standard for 30 days, then S3 One Zone-IA for 7 years.
Why it's wrong here
One Zone-IA is not durable enough for compliance.
✓
Use S3 Standard for 30 days, then transition to S3 Standard-IA, then to S3 Glacier Deep Archive after 90 days.
Why this is correct
Standard-IA for infrequent access, then Glacier Deep Archive for long-term retention.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
AWS often tests the misconception that S3 Intelligent-Tiering is always the most cost-effective for unknown access patterns, but in this scenario with a known access pattern (frequent for 30 days, then rarely), a lifecycle policy with explicit transitions is cheaper because it avoids the per-object monitoring fee of Intelligent-Tiering.
Detailed technical explanation
How to think about this question
S3 Glacier Deep Archive has a retrieval time of 12–48 hours and a storage cost of ~$0.00099/GB/month, making it ideal for compliance data that is rarely accessed. The lifecycle policy uses S3 Lifecycle rules to transition objects automatically; note that the minimum 30-day storage period for S3 Standard-IA must be respected, so transitioning after 30 days to Standard-IA and then after 90 days to Glacier Deep Archive avoids early deletion fees. Under the hood, S3 Lifecycle transitions are asynchronous and may take up to 48 hours to complete, but they are cost-effective for predictable access patterns.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use S3 Standard for 30 days, then transition to S3 Standard-IA, then to S3 Glacier Deep Archive after 90 days. — Option D is the most cost-effective because it matches the access pattern: S3 Standard for the first 30 days of frequent access, then S3 Standard-IA for the next 60 days (reduced storage cost with a retrieval fee), and finally S3 Glacier Deep Archive for the remaining ~6.9 years to meet the 7-year retention requirement at the lowest possible storage cost. This lifecycle policy minimizes total cost by transitioning data to progressively cheaper storage tiers as access frequency drops, while still meeting compliance.
What should I do if I get this DEA-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data engineer is designing a data lake on Amazon S3. The data is accessed frequently for the first 30 days, then rarely accessed after 90 days, and must be archived after 1 year. Which S3 lifecycle policy configuration meets these requirements with the lowest cost?
easy
A.Transition to S3 One Zone-IA after 30 days, then to S3 Glacier Deep Archive after 365 days.
B.Transition to S3 Glacier Flexible Retrieval after 90 days.
C.Transition to S3 Glacier Instant Retrieval after 30 days, then expire after 365 days.
✓ D.Transition to S3 Standard-IA after 30 days, then to S3 Glacier Deep Archive after 365 days.
Why D: Option B is correct because it transitions to S3 Standard-IA after 30 days (cost-effective for infrequent access) and to S3 Glacier Deep Archive after 365 days (lowest cost archival). Option A transitions to S3 One Zone-IA, which is not recommended for durability. Option C transitions to S3 Glacier Flexible Retrieval, which costs more than Deep Archive. Option D transitions to S3 Glacier Instant Retrieval, which is expensive for archival.
Last reviewed: Jun 30, 2026
Question Discussion
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This DEA-C01 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 DEA-C01 exam.
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