DEA-C01 Data Store Management Practice Question
A data engineer is designing a data lake on AWS using Amazon S3. The data consists of CSV files generated by IoT devices. The data is accessed by multiple analytics jobs, and the engineer needs to ensure that new files are immediately visible to all consumers after writing. What S3 consistency model applies?
⚠ Common exam trap
Candidates may incorrectly choose 'Read-after-write consistency for new object PUTS' (option D) because the question mentions new files after writing. While read-after-write behavior for new object PUTs is true, the current S3 consistency model is strong consistency for all operations. Another pitfall is selecting 'Eventual consistency for all operations' (option C) due to outdated knowledge of S3's previous eventual consistency model.
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
✓
Strong consistency for all operations.
Amazon S3 now provides strong consistency for all operations. After a successful write of a new object (or overwrite of an existing object), any subsequent read request immediately receives the latest version of the object, and list operations are also strongly consistent. Therefore, for new CSV files written to S3, the applicable model is strong consistency for all operations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Consistent reads require S3 Object Lock.
Why it's wrong here
S3 Object Lock enforces WORM retention and legal holds to prevent object deletion or overwriting; it has no bearing on read consistency. It is the correct control when regulatory retention or immutability of stored objects is required, not when ensuring newly written files are immediately readable.
- ✓
Strong consistency for all operations.
Why this is correct
Amazon S3 now provides strong read-after-write consistency for all PUT and DELETE operations across all Regions, so newly written IoT CSV objects are immediately visible to every analytics job. This satisfies the stem's requirement that new files be instantly visible to all consumers.
- ✗
Eventual consistency for all operations.
Why it's wrong here
Amazon S3 has provided strong read-after-write consistency for all PUT and DELETE operations since December 2020, so eventual consistency no longer applies to new object visibility. Eventual consistency described S3's pre-2020 behaviour and would only be relevant when reasoning about that historical model.
- ✗
Read-after-write consistency for new object PUTS.
Why it's wrong here
Read-after-write consistency for new object PUTs is a genuine S3 property, but the question asks which consistency model applies, and S3 now provides strong read-after-write consistency for all PUTs, overwrites and DELETEs, not merely new objects. Read-after-write was the accurate description under the older model.
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
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.