DBS-C01 Practice Test 2 — 10 Questions

Question 1

Arrange the steps to enable encryption at rest for an existing unencrypted Amazon RDS for MariaDB DB instance in the correct order.

Question 2

Arrange the steps to switch over from a primary Amazon RDS for Oracle DB instance to a standby in a Multi-AZ deployment (planned failover) in the correct order.

Question 3

Arrange the steps to create an Amazon DynamoDB global table (multi-Region) in the correct order.

Question 4

A company is migrating a 500 GB on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration must have minimal downtime and support ongoing replication after the initial load. Which AWS service should be used?

Accepted Answer

AWS Database Migration Service (DMS) with ongoing replication. AWS Database Migration Service (DMS) with ongoing replication (change data capture, CDC) is required because the scenario demands minimal downtime and continuous synchronization after the initial 500 GB load. DMS uses transaction logs (e.g., PostgreSQL WAL) to capture and apply ongoing changes, enabling a near-zero-duration cutover. Full load only (Option B) would cause downtime during the final sync and cannot support ongoing replication.

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS Database Migration Service (DMS) with full load only

Answer

AWS Glue

Question 5

A team is migrating an on-premises database to Amazon RDS using AWS DMS. After the full load completed, the task stopped. The team needs to perform ongoing replication to minimize downtime. What change should the team make to the DMS task?

Accepted Answer

Modify the replication task to change the migration type to 'full-load-and-cdc'.. After a full load completes and the task stops, the team needs to enable ongoing replication to capture and apply changes made to the source database during the migration window. Modifying the DMS task to use the 'full-load-and-cdc' migration type allows the task to perform the initial full load and then seamlessly transition to Change Data Capture (CDC) to replicate incremental changes, minimizing downtime. This is the correct approach because DMS supports switching a completed full-load task to include CDC without re-running the full load.

Answer

Restart the replication task with the same settings.

Answer

Create a new replication instance and start a new full-load task.

Answer

Use AWS Schema Conversion Tool to convert the schema again.

Question 6

A company is migrating an on-premises MongoDB database to Amazon DocumentDB (with MongoDB compatibility). They want to validate that the data is consistent after migration. Which tool should they use?

Accepted Answer

AWS DMS data validation. AWS DMS data validation is the correct tool because it provides built-in, row-level checksum-based validation that compares source and target data after a full load or ongoing replication. For DocumentDB migrations, DMS can compute and compare checksums on the fly, ensuring consistency without requiring manual scripting or external tools. This is the recommended AWS approach for validating data integrity during and after a migration to DocumentDB.

Answer

mongoexport and mongoimport

Answer

dbHash command on both databases

Answer

DocumentDB native consistency check tool

Question 7

A team is using AWS DMS to migrate a 3 TB Oracle database to Amazon Aurora PostgreSQL. They configured the task as shown. After the full load completes, they notice that the target tables have no indexes, primary keys, or foreign keys. What is the most likely cause?

Accepted Answer

The TargetTablePrepMode is set to DROP_AND_CREATE, which creates tables without indexes or constraints.. When TargetTablePrepMode is set to DROP_AND_CREATE, AWS DMS drops the target table if it exists and then creates a new one using only the basic column definitions from the source. It does not migrate indexes, primary keys, or foreign keys because DMS is not designed to replicate schema objects beyond table structure and data. To preserve constraints and indexes, you must either pre-create them on the target or use a different prep mode like TRUNCATE_BEFORE_LOAD.

Answer

The migration task did not include transformation rules to create indexes and constraints.

Answer

The table selection rule uses wildcards and excludes system tables, which also excludes index definitions.

Answer

The task is using a full load without LOB support, which prevents index creation.

Question 8

A company is migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The database uses SQL Server Agent jobs, custom CLR assemblies, and cross-database queries. Which of the following will require modification before migration?

Accepted Answer

SQL Server Agent jobs. SQL Server Agent jobs are not supported in Amazon RDS for SQL Server because RDS is a managed service that does not provide access to the underlying operating system or the SQL Server Agent service. To migrate job scheduling, you must use alternatives such as AWS Database Migration Service (DMS) tasks, AWS Lambda, or Amazon RDS for SQL Server native scheduling via stored procedures and Windows Task Scheduler on an EC2 instance.

Answer

Cross-database queries

Answer

Custom CLR assemblies

Answer

Stored procedures that use dynamic SQL

Question 9

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB and has a high number of small transactions. The company needs to minimize downtime during the migration. Which TWO strategies should be used together? (Choose two.)

Accepted Answer

Use AWS Database Migration Service (DMS) to perform a full load and ongoing replication.. AWS DMS with ongoing replication (CDC) is the correct choice because it allows a full load of the 2 TB database followed by continuous replication of changes, minimizing downtime by keeping the target RDS instance nearly synchronized with the source until cutover. This approach is specifically designed for large databases with high transaction volumes, as it reduces the final outage window to seconds or minutes.

Answer

Use Oracle Data Pump to export the database and import into RDS.

Answer

Set up a VPN connection between on-premises and AWS for direct database link.

Answer

Create a manual snapshot of the RDS instance during the migration.

Question 10

A company is running a production Amazon DynamoDB table with on-demand capacity. The table experiences occasional throttling during traffic spikes. The table's partition key is a timestamp, and the workload is write-heavy. The operations team needs to reduce throttling. Which THREE actions should the team take? (Choose three.)

Accepted Answer

Add a random suffix to the partition key to distribute writes evenly.. Option A is correct because adding a random suffix to the timestamp partition key breaks the sequential write pattern, distributing writes evenly across all partitions. This prevents hot partitions, which are the root cause of throttling in a write-heavy workload with a monotonically increasing partition key.

Answer

Increase the read capacity units for the table.

Answer

Enable DynamoDB global tables to distribute write traffic.