SAA-C03 Design Resilient Architectures Practice Question

A media company stores video files in an Amazon S3 bucket in the us-east-1 Region. The company wants to ensure that the files are automatically replicated to us-west-2 for disaster recovery, and that replication occurs within 15 minutes of upload. Which solution meets these requirements with the LEAST operational overhead?

⚠ Common exam trap

It's easy for candidates to confuse S3 Same-Region Replication with Cross-Region Replication, or assuming that a scheduled copy job can meet a near-real-time replication objective.

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 Cross-Region Replication (CRR) on the bucket with a replication rule that applies to all objects.

S3 Cross-Region Replication is the managed solution for automatically replicating objects to a bucket in another Region. It is asynchronous but typically completes within minutes, satisfying the 15-minute requirement. It requires versioning and an IAM role, but after setup it runs without ongoing intervention. This provides the lowest operational overhead compared to custom code or scheduled data transfer tasks.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Configure an AWS Lambda function triggered by S3 event notifications to copy each object to the destination bucket.
Why it's wrong here
A Lambda-based copy works but introduces custom code that must be maintained, monitored, and error-handled. It also may not meet the 15-minute window under heavy load or if the function fails. This approach has higher operational overhead than a managed replication feature and is less reliable for disaster recovery.
✗
Use AWS DataSync to schedule a recurring task that synchronizes the source bucket to the destination bucket every 15 minutes.
Why it's wrong here
DataSync is designed for large-scale data movement between on-premises storage and AWS, or between AWS storage services, but it is not event-driven. A scheduled task every 15 minutes may miss the window and requires managing task execution and reporting. It adds operational overhead and does not provide near-real-time replication.
✓
Enable S3 Cross-Region Replication (CRR) on the bucket with a replication rule that applies to all objects.
Why this is correct
S3 Cross-Region Replication automatically replicates objects to a bucket in another Region asynchronously, typically within minutes. It requires versioning on both buckets and an IAM role. Once configured, it operates with no additional infrastructure, providing low operational overhead and meeting the 15-minute replication goal for most objects.
✗
Enable S3 Same-Region Replication (SRR) to a bucket in us-east-1, then use S3 Batch Operations to copy objects to us-west-2 nightly.
Why it's wrong here
Same-Region Replication only replicates within the same Region, so it does not provide cross-Region disaster recovery. A nightly batch copy is far too slow to meet a 15-minute objective and requires manual job creation and monitoring. This combination does not satisfy the cross-Region and timeliness requirements.

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

SAA-C03 Design Resilient Architectures Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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