DEA-C01 Data Store Management Practice Question

A data engineer is designing a data lake on Amazon S3. The data lake will store raw data, transformed data, and curated datasets. The engineer needs to ensure that raw data is immutable (never overwritten or deleted) and that only authorized users can access the transformed data. Which combination of S3 features should the engineer use?

⚠ Common exam trap

The DEA-C01 exam often tests the distinction between versioning (which preserves history but allows overwrites) and Object Lock (which enforces immutability), leading candidates to choose versioning when immutability is explicitly required.

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

✓

Enable S3 Object Lock in compliance mode on the raw data prefix and use bucket policies to restrict access to transformed data prefix.

S3 Object Lock in compliance mode enforces a write-once-read-many (WORM) model, preventing any user—including the root user—from overwriting or deleting raw data. Bucket policies then provide granular access control to restrict the transformed data prefix to authorized users only, meeting both immutability and access control requirements.

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 Lifecycle policies to archive raw data to S3 Glacier and set bucket policies for transformed data.
Why it's wrong here
Lifecycle policies only transition or expire objects; they do not block overwrites or deletions, so raw data remains mutable. It is tempting because archiving to Glacier reduces cost and bucket policies restrict access, which suits long-term retention of data that need not be immutable.
✗
Enable S3 Versioning and use S3 Access Points for each prefix.
Why it's wrong here
Versioning preserves prior versions but still permits overwriting and deleting the current object, so immutability is not enforced. It is tempting because versioning plus Access Points gives per-prefix access control, which suits managing shared datasets rather than guaranteeing write-once raw storage.
✗
Enable default encryption with SSE-KMS and use S3 bucket policies to restrict access.
Why it's wrong here
SSE-KMS encrypts objects but does not prevent overwrites or deletions, so raw data immutability is unmet. It is tempting because encryption plus bucket policies secures access, which suits protecting transformed data confidentiality rather than enforcing write-once retention on the raw zone.
✓
Enable S3 Object Lock in compliance mode on the raw data prefix and use bucket policies to restrict access to transformed data prefix.
Why this is correct
S3 Object Lock in compliance mode enforces WORM protection, preventing any user, including the root account, from overwriting or deleting objects for the retention period — satisfying the immutability constraint on raw data. Bucket policies then restrict access to the transformed prefix, meeting the authorisation requirement.

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

DEA-C01 Data Store Management Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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