Question 392 of 1,040
Design Cost-Optimized ArchitecturesmediumMultiple ChoiceObjective-mapped

SAA-C03 S3 Cross-Region Replication (CRR) Practice Question

This SAA-C03 practice question tests your understanding of design cost-optimized architectures. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: s3 Cross-Region Replication (CRR). 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.

An application runs on EC2 in us-east-1 and frequently reads objects from an S3 bucket that is physically located in us-west-2. The finance team reports unexpectedly high inter-Region data transfer charges because the application retrieves objects for many user requests. A constraint: the bucket in us-west-2 must remain the system of record for compliance, but the application can read from a replica in us-east-1.

What should the solutions architect do to minimize network spend while meeting the compliance constraint?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "minimum / minimize"

    Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

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 from the us-west-2 source bucket to a destination bucket in us-east-1, and update the app to read from the us-east-1 bucket.

Option A is correct because enabling S3 Cross-Region Replication (CRR) automatically copies objects from the us-west-2 source bucket to a destination bucket in us-east-1, satisfying the compliance requirement that the us-west-2 bucket remains the system of record. By updating the application to read from the us-east-1 replica, all data retrieval traffic stays within the same region, eliminating inter-Region data transfer charges (which are typically $0.02/GB for S3 GET requests across regions). This approach directly addresses the cost issue while preserving the original bucket as the authoritative source.

Key principle: S3 Cross-Region Replication (CRR)

Answer analysis

Option-by-option breakdown

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

  • Enable S3 Cross-Region Replication from the us-west-2 source bucket to a destination bucket in us-east-1, and update the app to read from the us-east-1 bucket.

    Why this is correct

    CRR keeps the west bucket as the source of record while creating a near-region copy to reduce inter-Region transfer on reads.

    Clue confirmation

    The clue word "minimum / minimize" in the question point toward this answer.

    Related concept

    S3 Cross-Region Replication (CRR)

  • Create an interface VPC endpoint for S3 in us-east-1 and keep all object reads pointing to the us-west-2 bucket.

    Why it's wrong here

    VPC endpoints do not eliminate inter-Region transfer if the bucket remains in west; they only optimize private connectivity to the same Region.

  • Use VPC peering between two regions and route all requests to the us-west-2 bucket over the peering link.

    Why it's wrong here

    VPC peering does not remove inter-Region S3 data transfer charges and adds network complexity.

  • Use Route 53 latency-based routing to send users to a us-west-2 web endpoint and keep the S3 bucket unchanged.

    Why it's wrong here

    Routing user traffic to us-west-2 may help user latency, but it likely increases compute costs and still doesn’t address the read pattern cost driver.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may assume VPC endpoints or peering can magically route S3 traffic within a region, but S3 is a regional service and inter-Region data transfer charges apply regardless of the network path used.

Detailed technical explanation

How to think about this question

S3 Cross-Region Replication (CRR) uses asynchronous replication to copy objects to a destination bucket in another region, with replication typically completing within 15 minutes under normal conditions. The application can read from the replica using standard S3 GET requests, and since both the EC2 instance and the bucket are in us-east-1, data transfer is free (except for request costs). A subtle behavior: CRR requires versioning enabled on both source and destination buckets, and only new objects are replicated by default—existing objects must be replicated using S3 Batch Operations or a manual copy.

KKey Concepts to Remember

  • S3 Cross-Region Replication (CRR)
  • Inter-Region data transfer costs
  • System of record
  • Cost-optimized architecture

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

S3 Cross-Region Replication (CRR)

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.

Quick reference

AWS S3 Storage Class Comparison

Storage ClassMin DurationRetrievalUse Case
S3 StandardNoneImmediateFrequently accessed data
S3 Standard-IA30 daysImmediateInfrequent access, rapid retrieval
S3 One Zone-IA30 daysImmediateNon-critical infrequent data
S3 Intelligent-TieringNoneImmediate–hoursUnknown or changing access patterns
S3 Glacier Instant90 daysMillisecondsArchive with instant retrieval
S3 Glacier Flexible90 daysMinutes–hoursArchive, flexible retrieval
S3 Glacier Deep Archive180 daysHoursLong-term compliance archive

What to study next

Got this wrong? Here's your next step.

Review s3 Cross-Region Replication (CRR), then practise related SAA-C03 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this SAA-C03 question test?

Design Cost-Optimized Architectures — This question tests Design Cost-Optimized Architectures — S3 Cross-Region Replication (CRR).

What is the correct answer to this question?

The correct answer is: Enable S3 Cross-Region Replication from the us-west-2 source bucket to a destination bucket in us-east-1, and update the app to read from the us-east-1 bucket. — Option A is correct because enabling S3 Cross-Region Replication (CRR) automatically copies objects from the us-west-2 source bucket to a destination bucket in us-east-1, satisfying the compliance requirement that the us-west-2 bucket remains the system of record. By updating the application to read from the us-east-1 replica, all data retrieval traffic stays within the same region, eliminating inter-Region data transfer charges (which are typically $0.02/GB for S3 GET requests across regions). This approach directly addresses the cost issue while preserving the original bucket as the authoritative source.

What should I do if I get this SAA-C03 question wrong?

Review s3 Cross-Region Replication (CRR), then practise related SAA-C03 questions on the same topic to reinforce the concept.

Are there clue words in this question I should notice?

Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

What is the key concept behind this question?

S3 Cross-Region Replication (CRR)

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Last reviewed: Jun 11, 2026

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This SAA-C03 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 SAA-C03 exam.