The answer is to use AWS Database Migration Service (DMS) with ongoing replication. This is the correct choice because DMS’s change data capture (CDC) feature reads Oracle’s redo logs to continuously replicate writes to Aurora PostgreSQL, enabling a full load of the 10 TB database followed by near-zero-downtime synchronization until a brief cutover. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of heterogeneous migrations with minimal downtime, often contrasting DMS with offline tools like Oracle Data Pump or AWS Snowball. A common trap is choosing a snapshot or export/import approach, which would cause extended downtime for a heavily written database. Remember the key distinction: if the source has constant writes and you need minimal downtime, you must use ongoing replication, not a one-time load. Memory tip: “CDC for constant writes” — if the database never sleeps, DMS with CDC is what you keep.
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. 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 company is using Amazon RDS for Oracle with a very large database (10 TB). They need to migrate to Amazon Aurora PostgreSQL with minimal downtime. The source database is heavily used with constant writes. Which migration strategy is most appropriate?
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 to migrate from Oracle to Aurora PostgreSQL.
AWS DMS with ongoing replication (change data capture) is the most appropriate strategy for migrating a heavily written 10 TB Oracle database to Aurora PostgreSQL with minimal downtime. DMS can perform a full load of the existing data and then continuously replicate changes from Oracle's redo logs to Aurora PostgreSQL, allowing the source to remain fully operational until a brief cutover window. This approach minimizes downtime compared to offline export/import methods and is natively supported by AWS.
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.
✗
Export the Oracle database using expdp and import into Aurora PostgreSQL using pg_restore.
Why it's wrong here
This requires downtime and does not support continuous replication.
✓
Use AWS Database Migration Service (DMS) with ongoing replication to migrate from Oracle to Aurora PostgreSQL.
Why this is correct
DMS supports full load and CDC, minimizing downtime.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create a read replica of the RDS Oracle instance and promote it to an Aurora PostgreSQL instance.
Why it's wrong here
Cross-engine replication is not supported for read replicas.
✗
Use Oracle GoldenGate to replicate data to an Aurora PostgreSQL instance.
Why it's wrong here
GoldenGate is not managed by AWS and requires additional licensing and complexity.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse read replicas (which are engine-specific and cannot change database engines) with DMS replication, or assume that Oracle GoldenGate is always the best choice for heterogeneous migrations without considering AWS-native alternatives like DMS.
Detailed technical explanation
How to think about this question
DMS uses Oracle LogMiner or binary reader to capture changes from redo logs for ongoing replication, supporting both full load and change data capture (CDC) phases. For a 10 TB database, DMS can parallelize the full load across multiple tables and then apply CDC to keep the target in sync, with a final cutover that typically takes minutes. A key consideration is that DMS requires supplemental logging to be enabled on the Oracle source to capture all changes, and it handles data type conversions (e.g., NUMBER to NUMERIC) automatically, but you must validate large objects (LOBs) and any unsupported data types beforehand.
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.
Workload-Specific Database Design — This question tests Workload-Specific Database Design — 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 to migrate from Oracle to Aurora PostgreSQL. — AWS DMS with ongoing replication (change data capture) is the most appropriate strategy for migrating a heavily written 10 TB Oracle database to Aurora PostgreSQL with minimal downtime. DMS can perform a full load of the existing data and then continuously replicate changes from Oracle's redo logs to Aurora PostgreSQL, allowing the source to remain fully operational until a brief cutover window. This approach minimizes downtime compared to offline export/import methods and is natively supported by AWS.
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.
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Question Discussion
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