The answer is AWS Database Migration Service (DMS). This is the correct choice because DMS supports ongoing change data capture (CDC) replication, which allows you to migrate an Oracle database to Amazon RDS for Oracle with minimal downtime by continuously syncing transactions from the source to the target during the migration window. For a 2 TB database with a high transaction rate, DMS’s CDC capability ensures that only a brief cutover pause is needed, rather than a full outage. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of migration strategies under the “Migration and Management” domain; a common trap is confusing AWS Schema Conversion Tool (SCT) with DMS—SCT handles schema conversion but not data replication, while DMS handles the actual ongoing sync. Another trap is selecting Snowball, which is for offline bulk transfers and cannot achieve minimal downtime. Memory tip: think “DMS = Data Moves Sync” for ongoing replication, while SCT = Schema Conversion Tool only.
DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. 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 migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a high transaction rate. The migration must have minimal downtime and support ongoing replication. Which AWS service should be used for the migration?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
AWS Database Migration Service (AWS DMS)
AWS Database Migration Service (DMS) supports ongoing replication from Oracle to RDS Oracle with minimal downtime. AWS SCT helps convert the schema but does not perform replication. RDS Read Replicas are for RDS to RDS, not on-premises to RDS. Direct Connect provides a network connection but does not handle data migration. Snowball is for offline data transfer, not minimal downtime.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
AWS Schema Conversion Tool (AWS SCT)
Why it's wrong here
AWS SCT is used for schema conversion, not for data replication or migration with minimal downtime.
✓
AWS Database Migration Service (AWS DMS)
Why this is correct
AWS DMS supports ongoing replication from on-premises to RDS, enabling minimal downtime migrations.
Related concept
Standard ACLs match source addresses.
✗
AWS Direct Connect
Why it's wrong here
Direct Connect provides a dedicated network connection but does not perform data migration.
✗
Amazon RDS Read Replica
Why it's wrong here
Read Replicas are for RDS instances, not for on-premises databases.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
Deployment and Migration — This question tests Deployment and Migration — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: AWS Database Migration Service (AWS DMS) — AWS Database Migration Service (DMS) supports ongoing replication from Oracle to RDS Oracle with minimal downtime. AWS SCT helps convert the schema but does not perform replication. RDS Read Replicas are for RDS to RDS, not on-premises to RDS. Direct Connect provides a network connection but does not handle data migration. Snowball is for offline data transfer, not minimal downtime.
What should I do if I get this DBS-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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 company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database uses Oracle Data Pump for export/import. The migration must be completed within a short maintenance window. Which migration approach should they use?
medium
A.Use AWS Snowball to transfer the database files to AWS and then restore to RDS.
✓ B.Use AWS Database Migration Service with full load and change data capture (CDC).
C.Use Oracle Data Pump to export the database and import into RDS.
D.Use AWS Schema Conversion Tool (SCT) to convert the schema and then use DMS for data migration.
Why B: Option A (Use AWS DMS with a full load + CDC) is correct because it minimizes downtime by capturing changes. Option B (Use Oracle Data Pump export/import) requires significant downtime. Option C (Use AWS SCT to convert schema and then use DMS) is unnecessary if staying on Oracle. Option D (Use AWS Snowball) is for large data transfers, not for minimal downtime.
Variation 2. A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 5 TB in size and has a daily change rate of 2%. The migration must have minimal downtime. Which migration strategy should be used?
medium
A.Use AWS Schema Conversion Tool (SCT) to convert the schema, then use AWS DMS for full load only.
B.Create an RDS read replica in the same region and promote it.
✓ C.Use AWS Database Migration Service (DMS) with ongoing replication from the source database.
D.Export the database to a dump file using Oracle Data Pump, upload to S3, and restore to RDS.
Why C: AWS DMS with ongoing replication allows continuous data sync with minimal downtime. Option A (AWS SCT + DMS) is not ideal because SCT is for schema conversion, not needed here. Option C (export/import) causes downtime. Option D (RDS read replica) is for within AWS, not on-premises to RDS.
Variation 3. A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 1 TB and has a large number of stored procedures and triggers. The migration must minimize application changes. Which migration approach should be used?
medium
A.Use AWS Schema Conversion Tool (AWS SCT) to convert the schema and AWS DMS for data migration
✓ B.Use AWS Database Migration Service (AWS DMS) with full load and ongoing replication
C.Use Oracle Data Pump (expdp/impdp) to export and import the database
D.Use AWS S3 to store the data and AWS Glue to transform and load into RDS
Why B: AWS DMS with ongoing replication allows for minimal downtime and can migrate data while keeping the source database running. Option A is incorrect because expdp/impdp does not support ongoing replication. Option C is incorrect because using S3 as an intermediate step adds complexity. Option D is incorrect because AWS SCT is for schema conversion, not data migration.
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Question Discussion
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