The correct approach is to use AWS Database Migration Service (DMS) with ongoing replication via change data capture (CDC). This method is essential for an Oracle to Aurora PostgreSQL migration with minimal downtime because DMS first performs a full load of the source database and then continuously captures and applies incremental changes from Oracle’s redo logs to the target Aurora PostgreSQL instance. At cutover, you simply stop new writes to Oracle, let CDC catch up, and redirect traffic—ensuring data consistency without a lengthy maintenance window. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of heterogeneous migrations and the critical role of CDC for near-zero downtime. A common trap is choosing a snapshot-based approach or a simple one-time export/import, which would require significant downtime. Remember the memory tip: “CDC keeps the clock ticking” — it’s the only way to keep changes flowing live during migration.
DBS-C01 Management and Operations Practice Question
This DBS-C01 practice question tests your understanding of management and operations. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
A database team is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The team needs to ensure minimal downtime and data consistency. Which approach should be used?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use AWS Database Migration Service (DMS) with ongoing replication using change data capture (CDC)
AWS DMS with ongoing replication using change data capture (CDC) is the correct approach because it enables a live migration with minimal downtime. DMS can perform a full load of the Oracle database and then continuously replicate ongoing changes from Oracle to Aurora PostgreSQL, ensuring data consistency at the point of cutover. This method avoids the need for a long maintenance window and supports heterogeneous migrations with automatic schema conversion.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 the PostgreSQL foreign data wrapper (FDW) to link the Oracle database
Why it's wrong here
FDW is for querying, not for migration with minimal downtime.
✗
Use AWS Server Migration Service (SMS) to replicate the database
Why it's wrong here
SMS is for server migration, not databases.
✓
Use AWS Database Migration Service (DMS) with ongoing replication using change data capture (CDC)
Why this is correct
DMS with CDC minimizes downtime by replicating changes continuously.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use pg_dump and pg_restore to migrate the data during a maintenance window
Why it's wrong here
This requires downtime and may not handle ongoing changes.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse AWS DMS with simpler dump-and-restore tools (pg_dump/pg_restore) or assume that a foreign data wrapper can perform a migration, when in fact DMS is the only AWS managed service designed specifically for heterogeneous database migrations with minimal downtime via CDC.
Detailed technical explanation
How to think about this question
AWS DMS uses a replication instance to connect to the source Oracle database via Oracle LogMiner or binary reader to capture changes from redo logs, and then applies them to the target Aurora PostgreSQL using native PostgreSQL interfaces. The CDC process ensures that transactions are applied in the same order and with the same isolation level as on the source, maintaining ACID consistency. In real-world scenarios, DMS can handle large volumes of ongoing changes (e.g., thousands of transactions per second) by batching and parallelizing apply operations, but careful tuning of task settings (e.g., MaxFullLoadSubTasks, BatchApplyEnabled) is critical to avoid lag or target contention.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Management and Operations — This question tests Management and Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use AWS Database Migration Service (DMS) with ongoing replication using change data capture (CDC) — AWS DMS with ongoing replication using change data capture (CDC) is the correct approach because it enables a live migration with minimal downtime. DMS can perform a full load of the Oracle database and then continuously replicate ongoing changes from Oracle to Aurora PostgreSQL, ensuring data consistency at the point of cutover. This method avoids the need for a long maintenance window and supports heterogeneous migrations with automatic schema conversion.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A team is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. The database is 2 TB and has a 6-hour maintenance window. Which AWS service should the team use to minimize downtime?
medium
✓ A.AWS Database Migration Service (AWS DMS)
B.Amazon S3 Transfer Acceleration
C.AWS Snowball Edge
D.Amazon EC2 with Oracle installed
Why A: AWS DMS is the correct choice because it can perform a live migration from Oracle to Aurora PostgreSQL with minimal downtime using ongoing replication (change data capture). It supports heterogeneous migrations, automatically converting the source schema and data types, and can handle a 2 TB database within the 6-hour maintenance window by using multiple parallel tasks and large instance types.
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This DBS-C01 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 DBS-C01 exam.
Question Discussion
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