Which S3 Lifecycle Policy Meets High Availability and Lowest Cost?

DEA-C01 By islever Editorial Last updated

Manage the lifecycle of data. Choose a data store.

Short answer

C Use an S3 Lifecycle policy to move objects to S3 Standard-IA after 6 months and to S3 Glacier Deep Archive after 2 years for high availability at lowest cost.

Question

A company currently stores all of its data in Amazon S3 by using the S3 Standard storage class. A data engineer examined data access patterns to identify trends. During the first 6 months, most data files are accessed several times each day. Between 6 months and 2 years, most data files are accessed once or twice each month. After 2 years, data files are accessed only once or twice each year. The data engineer needs to use an S3 Lifecycle policy to develop new data storage rules. The new storage solution must continue to provide high availability. Which solution will meet these requirements in the MOST cost-effective way?
  1. Transition objects to S3 One Zone-Infrequent Access (S3 One Zone-IA) after 6 months. Transfer objects to S3 Glacier Flexible Retrieval after 2 years.
  2. Transition objects to S3 Standard-Infrequent Access (S3 Standard-IA) after 6 months. Transfer objects to S3 Glacier Flexible Retrieval after 2 years.
  3. Transition objects to S3 Standard-Infrequent Access (S3 Standard-IA) after 6 months. Transfer objects to S3 Glacier Deep Archive after 2 years. Correct Answer
  4. Transition objects to S3 One Zone-Infrequent Access (S3 One Zone-IA) after 6 months. Transfer objects to S3 Glacier Deep Archive after 2 years.

Key Takeaways

It tests matching S3 storage-class access patterns and the high-availability constraint, and the trap is choosing Glacier Flexible Retrieval or One Zone-IA without a stated retrieval-time or single-AZ tradeoff.

This DEA-C01 question tests an S3 Lifecycle policy that moves aging data from S3 Standard to the cheapest storage class while preserving high availability. The answer is C: S3 Standard-IA after 6 months, then S3 Glacier Deep Archive after 2 years.

Common mistake: Many learners choose B (S3 Glacier Flexible Retrieval) because it offers faster retrieval and is documented for once- or twice-yearly access, but the question states no retrieval-time requirement, so it is not the most cost-effective option; others choose One Zone-IA and miss the high-availability requirement.

Expert Analysis

Why the Answer Is Correct

C is correct because the access pattern starts with frequent daily reads, then drops to once or twice a month after 6 months, and finally to once or twice a year after 2 years. S3 Standard-IA is the appropriate lifecycle transition after 6 months for infrequent monthly access, and S3 Glacier Deep Archive is the lowest-cost archive class for data accessed only once or twice per year. The requirement says the solution must "continue to provide high availability," and both S3 Standard-IA and S3 Glacier Deep Archive are designed for high durability and multi-AZ availability. Because no retrieval-time objective is stated, paying for Glacier Flexible Retrieval's faster retrieval would be unnecessary. This combination satisfies high availability while minimizing storage cost across the full lifecycle.

Why the Other Options Are Wrong

A and D both transition to S3 One Zone-IA after 6 months, which stores data in a single Availability Zone and therefore does not meet the high-availability requirement. B correctly uses S3 Standard-IA after 6 months, but it transitions to S3 Glacier Flexible Retrieval after 2 years; Flexible Retrieval costs more than Deep Archive and its faster retrieval speed is not required. Option C is therefore more cost-effective than B for the stated annual access pattern. No option preserves S3 Standard after 6 months, but keeping Standard would also be more expensive than Standard-IA for monthly access.

Community Comment Notes

The community is split, with the source key and a majority favoring C while a sizable minority selects B. As michele_scar put it, "deleting A and D for the HA, remains B and C," which captures the first elimination step cleanly. Udyan argued that retrieval time is not a constraint and concluded that "deep archive will save costs only," reflecting the no-latency-requirement logic. helpaws quoted AWS documentation that Glacier Flexible Retrieval is for data accessed 1-2 times per year, which is accurate but does not prove it is cheaper than Deep Archive. anonymous_learner_2 noted "there's no retrieval time requirement so C is the most cost effective," matching the exam's cost priority.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

In S3 lifecycle questions, first remove any storage class that violates an explicit constraint such as high availability; S3 One Zone-IA is the usual trap because it is cheap but single-AZ. Then compare the remaining archive classes by whether the scenario states a retrieval-time requirement; if none exists, Glacier Deep Archive is normally the most cost-effective final tier.

Frequently Asked Questions

Why is S3 One Zone-IA wrong for this S3 Lifecycle policy?

S3 One Zone-IA stores data in a single Availability Zone, so it does not meet the question's explicit high-availability requirement even though it is cheaper than S3 Standard-IA.

Why choose Glacier Deep Archive over Glacier Flexible Retrieval after 2 years?

The files are accessed only once or twice yearly and no retrieval-time requirement is stated, so Deep Archive's lower storage cost makes it more cost-effective than Flexible Retrieval.

More DEA-C01 FAQ →

Community Votes

C
58%
B
42%

58% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 36 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 30 of 36

  1. helpaws 👍 19 Answered B
    "S3 Glacier Flexible Retrieval delivers low-cost storage, up to 10% lower cost (than S3 Glacier Instant Retrieval), for archive data that is accessed 1-2 times per year and is retrieved asynchronously" Source: https://aws.amazon.com/s3/storage-classes/glacier/
  2. WarPig666 👍 7 Answered C
    Flexible retrieval will be higher cost than deep archive. If records only need to be retrieved once or twice a year, this doesn't mean they need to be instantly available.
  3. GiorgioGss 👍 4 Answered C
    The new storage solution must continue to provide high availability = A and C out. After 2 years, data files are accessed only once or twice each year. && MOST cost-effective way = C. C is more cost-effective than B.
  4. lucas_rfsb 👍 4 Answered C
    Since it was requested high availability, then can't be Standard One Zone. And in the end of 2 years it was asked for the most cost effective, than Glacier Deep Archive.
  5. altonh 👍 4 Answered C
    There is no requirement for the retrieval time. So this is more cost-effective.
Show 25 more comments
  1. michele_scar 👍 3 Answered C
    It's C, the request is about "High availability" not "Less time to retrieve the data". The other request is "most cost effective" so deleting A and D for the HA, remains B and C that both satisfy the HA. Now choose the most cost effective --> C
  2. TonyStark0122 👍 3
    Option B: Transition objects to S3 Standard-Infrequent Access (S3 Standard-IA) after 6 months. Transfer objects to S3 Glacier Flexible Retrieval after 2 years.
  3. iamwatchingyoualways 👍 3 Answered C
    No instant access is mentioned. Most Cost effective.
  4. truongnguyen86 👍 2 Answered B
    Option B is the correct answer because it balances cost-effectiveness and availability: S3 Standard-IA offers cost savings for infrequently accessed data while maintaining high availability across multiple zones. S3 Glacier Flexible Retrieval is a good balance for archiving with occasional access needs.
  5. Udyan 👍 2 Answered C
    Is it mentioned in question that Retrieval time is constraint, no, so, if any engineer need to access data, say May and November, so he/she can wait for 2-3 days to get data, as in the long run, they have an year to analyze the data so, deep archive will save costs only.
  6. anonymous_learner_2 👍 2 Answered C
    Glacier deep archive has the same availability as flexible retrieval and there's no retrieval time requirement so C is the most cost effective that meets the requirements.
  7. blackgamer 👍 2 Answered C
    The question mention "the most cost-effective way". C is most cost-effective and still highly available. The requirement doesn't indicate the retrieval time requirement.
  8. Udyan 👍 2 Answered C
    This question was in Stephen Maarek Udemy practice questions too, here concern not given for extraction time so, just see cost friendlyness, thus, C over B
  9. LR2023 👍 2
    questions doesnt provide clairty on when data is accessed does it need to made available instantly or not. Deep archive times are longer.
  10. andrologin 👍 2 Answered B
    Based on this link https://aws.amazon.com/s3/storage-classes/glacier/ Glacier Flexible Retrieval is cheaper that Instant Retrieval
  11. arvehisa 👍 2 Answered C
    2 requirements: 1)highly available 2) cost-effective. no mention about load time so C is correct.
  12. Just_Ninja 👍 2 Answered C
    HA and cost effective. Here is no hint in the question for instant access..
  13. jk15997 👍 2 Answered C
    There is no requirement for the retrieval time.
  14. sachin 👍 1
    • S3 Glacier Instant Retrieval delivers the lowest cost storage, up to 68% lower cost (than S3 Standard-Infrequent Access), for long-lived data that is accessed once per quarter and requires millisecond retrieval. • S3 Glacier Flexible Retrieval delivers low-cost storage, up to 10% lower cost (than S3 Glacier Instant Retrieval), for archive data that is accessed 1-2 times per year and is retrieved asynchronously. • S3 Glacier Deep Archive delivers the lowest cost storage, up to 75% lower cost (than S3 Glacier Flexible Retrieval), for long-lived archive data that is accessed less than once per year and is retrieved asynchronously.
  15. Rpathak4 👍 1 Answered C
    Why Not the Other Options? A. S3 One Zone-IA → Glacier Flexible Retrieval ❌ One Zone-IA is risky (data loss if the AZ fails). Glacier Flexible Retrieval is more expensive than Deep Archive. B. S3 Standard-IA → Glacier Flexible Retrieval ❌ Glacier Flexible Retrieval is not the cheapest long-term storage. Deep Archive costs much less. D. S3 One Zone-IA → Glacier Deep Archive ❌ One Zone-IA lacks high availability (single AZ failure = data loss). S3 Standard-IA is safer.
  16. lsj900605 👍 1 Answered B
    B High availability means the need for readily available service. S3 Standard-IA deliver 99.9% availability vs S3 One Zone-IA deliver 99.5% availability S3 Glacier Flexible Retrieval has configurable retrieval times, from minutes to hours, with free bulk retrievals. But with S3 Glacier Deep Archive it's retrieval time is within 12 hours https://aws.amazon.com/s3/storage-classes/
  17. Fexo 👍 1 Answered B
    Answer is B, because Object needs to be retrieved once / twice monthly , hence GFR S3 Glacier Flexible Retrieval delivers low-cost storage, up to 10% lower cost (than S3 Glacier Instant Retrieval), for archive data that is accessed 1-2 times per year and is retrieved asynchronously https://aws.amazon.com/s3/storage-classes/glacier/
  18. Khooks 👍 1 Answered C
    Answer should be C. B: While this option transitions to S3 Glacier Flexible Retrieval after 2 years, which provides quicker retrieval times than Glacier Deep Archive, it is more expensive. Given the infrequent access pattern after 2 years, the additional cost is not justified.
  19. shammous 👍 1 Answered B
    To retrieve data from the S3 Glacier Deep Archive, you need more than 12 hours! The scenario mentions that we still need to access data instantly once or twice yearly. S3 Glacier Flexible Retrieval is more appropriate in this case.
  20. GZMartinelli 👍 1 Answered B
    Should be B. The questions asks for high availability, when a file is in Glacier Deep Archive, it takes more time to be available to use.
  21. imymoco 👍 1
    B https://aws.amazon.com/jp/about-aws/whats-new/2021/11/amazon-s3-glacier-storage-class-amazon-s3-glacier-flexible-retrieval/
  22. plutonash 👍 1 Answered B
    "data files are accessed only once or twice each year", this is "S3 Glacier Flexible Retrieval" definition
  23. tgv 👍 1 Answered C
    I will go with C because Glacier Flexible Retrieval is way more expensive than Glacier Deep Archive.
  24. theloseralreadytaken 👍 1 Answered B
    Galcier Deep Archive take longer retrieval time (hours to days) than Glacier Flexible Retrieval.
  25. CalvinL4 👍 1
    C is wrong. Deep archive requires very long to load.

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