A Database Specialist is migrating a 2 TB Amazon RDS for Oracle DB instance to an RDS for PostgreSQL DB instance using AWS DMS. The source RDS Oracle DB instance is in a VPC in the us-east-1 Region…

Question

Options

• AIn the same Region and VPC of the source DB instance
• BIn the same Region and VPC as the target DB instance
• CIn the same VPC and Availability Zone as the target DB instance
• DIn the same VPC and Availability Zone as the source DB instance

• A
  8% (4)
• B
  4% (2)
• C
  71% (35)
• D
  16% (8)

Explanation

Explanation

Placing the AWS DMS replication instance in the same VPC and Availability Zone as the target DB instance (us-west-2) is optimal because DMS reads data from the source once but writes continuously to the target during the migration, making the write path the performance bottleneck - minimizing latency on the target side yields the greatest overall benefit.

Why the distractors are wrong:

• Option A places DMS close to the source (us-east-1/same VPC), which reduces read latency but creates high-latency writes across regions to the target - the slower leg of the migration.
• Option B is close but incomplete - being in the same Region as the target is good, but not specifying the same Availability Zone means data could still cross AZ boundaries, adding unnecessary latency and potential data transfer costs.
• Option D similarly prioritizes the source side and also specifies the same AZ as the source, which doesn't address the write-side bottleneck.

Memory Tip: Think of DMS like a delivery truck - it's more important to park it close to the delivery destination (target) than close to the warehouse (source), and parking it in the exact same neighborhood (same AZ) avoids extra driving costs. "Target + Same AZ = Best Performance."

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