AWS DMS Replication Instance Region for Cross-Region Migration

DEA-C01 By islever Editorial Last updated

Automate data processing by using AWS services.

Short answer

A Set up an AWS DMS replication instance in Account_B in eu-west-1 to satisfy the co-location requirement for Amazon Redshift targets.

Question

A company wants to migrate data from an Amazon RDS for PostgreSQL DB instance in the eu-east-1 Region of an AWS account named Account_A. The company will migrate the data to an Amazon Redshift cluster in the eu-west-1 Region of an AWS account named Account_B. Which solution will give AWS Database Migration Service (AWS DMS) the ability to replicate data between two data stores?
  1. Set up an AWS DMS replication instance in Account_B in eu-west-1. Correct Answer
  2. Set up an AWS DMS replication instance in Account_B in eu-east-1.
  3. Set up an AWS DMS replication instance in a new AWS account in eu-west-1.
  4. Set up an AWS DMS replication instance in Account_A in eu-east-1.

Key Takeaways

The core trap is assuming the replication instance must match the source region; however, for Amazon Redshift targets, the DMS instance must reside in the same region as the target cluster.

This question addresses the placement of an AWS DMS replication instance when migrating data between different AWS accounts and regions, specifically involving Amazon Redshift as the target.

Common mistake: Many learners incorrectly choose Option D or B, believing the replication instance should be colocated with the source database (RDS) to minimize latency or simplify networking, ignoring the specific Redshift constraint.

Expert Analysis

Why the Answer Is Correct

The correct answer is A because AWS Database Migration Service (DMS) has a specific architectural requirement for Amazon Redshift targets: the replication instance must be deployed in the same AWS Region as the Redshift cluster. In this scenario, the target is in eu-west-1, so the replication instance must also be in eu-west-1. While it is common practice to place the DMS instance in the same region as the source for performance reasons with other databases (like RDS), Redshift requires co-location for VPC peering and endpoint configuration constraints.

Why the Other Options Are Wrong

Option B places the instance in eu-east-1 (source region), which violates the Redshift co-location rule. Option C suggests a new account, which adds unnecessary complexity without solving the regional constraint. Option D is incorrect for the same reason as B; placing the instance in Account_A's source region prevents proper connectivity to the Redshift cluster in eu-west-1 under standard DMS configurations for Redshift.

Community Comment Notes

Community comments heavily support Option A, citing official AWS documentation that states the replication instance must be in the same region as the Redshift target. Comments from users like 'andrologin' and 'lool' explicitly reference the prerequisite documentation. One user, 'samadal', incorrectly argued for Option D based on a general cross-region migration rule, but failed to account for the specific Redshift exception, leading to confusion among some voters.

Official Reference

https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Target.Redshift.html#CHAP_Target.Redshift.Prerequisites

This link opens the official vendor documentation in a new tab.

Exam Strategy

Always check if the target database type imposes specific regional constraints on the DMS replication instance. For Redshift, the rule is strict: same region as the target. For most other sources/targets, the instance can be anywhere with network access, but colocation with the source is often preferred for performance.

Frequently Asked Questions

Why can't DMS replicate from eu-east-1 to eu-west-1 directly?

DMS instances are regional resources. For Redshift, the instance MUST be in the same region as the target cluster due to VPC and endpoint constraints.

Is the DMS instance always in the source region?

No. While often placed near the source for performance, it must be in the same region as the target if the target is Amazon Redshift.

More DEA-C01 FAQ →

Community Votes

A
84%
B
16%

84% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 8 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 8

  1. andrologin 👍 5 Answered A
    Redshift needs to be in the same region as the replication instance see docs: https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Target.Redshift.html#CHAP_Target.Redshift.Prerequisites
  2. lool 👍 4 Answered A
    Redshift has to be in the same region as the DMS https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Target.Redshift.html#CHAP_Target.Redshift.Prerequisites
  3. HunkyBunky 👍 2 Answered B
    B - becuase AWS DMS must be in a same region as AWS redshift cluster https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Target.Redshift.html#CHAP_Target.Redshift.Prerequisites
  4. bakarys 👍 1 Answered A
    To enable AWS Database Migration Service (AWS DMS) to replicate data between two data stores in different AWS Regions, you should choose option A. Here’s why: Option A: Set up an AWS DMS replication instance in Account_B in eu-west-1. This approach allows you to configure replication between the Amazon RDS for PostgreSQL DB instance in eu-east-1 and the Amazon Redshift cluster in eu-west-1. By using AWS DMS, you can efficiently migrate data across Regions while minimizing downtime and ensuring data consistency
  5. samadal 👍 1 Answered D
    When you use WS DMS to migrate data between different AWS Regions or accounts, you must remember the following: The replication instance must be created in the same Region as the source database. The target endpoint must be created in the Region where the target data store is located. You must set up the required IAM roles and permissions to enable DMS to access the source and target resources.
Show 3 more comments
  1. sdas1 👍 1
    The correct solution to replicate data between the Amazon RDS for PostgreSQL DB instance in Account_A (eu-east-1) and the Amazon Redshift cluster in Account_B (eu-west-1) using AWS Database Migration Service (AWS DMS) is: A. Set up an AWS DMS replication instance in Account_B in eu-west-1.
  2. sdas1 👍 1
    https://docs.aws.amazon.com/dms/latest/userguide/CHAP_ReplicationInstance.VPC.html
  3. Bmaster 👍 1
    My Choice is D

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