DBS-C01 Deployment and Migration Practice Test 2 — 15 Questions

Question 1

A company is migrating a self-managed PostgreSQL database to Amazon Aurora PostgreSQL. They want to use the pglogical extension for logical replication to minimize downtime. Which THREE prerequisites must be met before setting up pglogical?

Accepted Answer

Add pglogical to shared_preload_libraries and restart the source database. Option A is correct because pglogical must be loaded into the shared preload libraries on the source PostgreSQL instance so that it is available at server start. Without this, the extension cannot be installed or used. The database must be restarted after modifying shared_preload_libraries for the change to take effect.

Answer

Configure max_wal_senders to at least 10

Answer

Enable track_commit_timestamp on the source

Question 2

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. The network link has limited bandwidth, and the company wants to avoid costly data transfer fees. Which approach should be used?

Accepted Answer

Use AWS DMS with ongoing replication (CDC) from the start.. AWS DMS with ongoing replication (CDC) enables a full load followed by continuous change data capture, which meets the requirements of minimal downtime and ongoing replication. DMS compresses data in transit and can throttle network usage, helping to manage limited bandwidth and avoid costly data transfer fees by using the existing network link efficiently.

Answer

Use AWS Database Migration Service (DMS) with a full load only, then cut over.

Answer

Use pg_dump to export the database and pg_restore to import into RDS.

Answer

Use AWS Snowball Edge to transfer the database files, then load into RDS.

Question 3

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 4

A company is migrating a 2 TB MySQL database from on-premises to Amazon RDS for MySQL. They need to minimize downtime and ensure data consistency. They plan to use AWS DMS. What is the first step they should take before starting the migration task?

Accepted Answer

Enable binary logging (binlog) on the source MySQL database.. AWS DMS requires binary logging (binlog) to be enabled on the source MySQL database to capture ongoing changes during the full-load and change data capture (CDC) phase. This ensures data consistency and minimizes downtime by allowing DMS to replicate incremental changes after the initial load. Without binlog, DMS cannot perform CDC, and the migration would be limited to a one-time snapshot, risking data loss or extended downtime.

Answer

Create a read replica of the source database to reduce load.

Answer

Disable foreign key checks on the source database to speed up the load.

Answer

Enable binary logging on the target RDS for MySQL instance.

Question 5

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

Accepted Answer

Use AWS Database Migration Service (DMS) with a full load and ongoing replication from a change data capture source.. AWS DMS is the correct choice because it supports both a full load of the 500 GB database and ongoing replication using change data capture (CDC) from the on-premises MySQL source. This enables minimal downtime by keeping the target RDS instance synchronized during the migration window, and it handles schema conversion automatically for MySQL-to-MySQL migrations without needing a separate tool.

Answer

Use mysqldump to export the database and import to RDS during a maintenance window.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema and migrate data.

Answer

Take a physical backup, copy it to Amazon S3, and restore to RDS.

Question 6

A company is planning to migrate a 2 TB Oracle database to Amazon Aurora PostgreSQL. The database contains large objects (LOBs) and uses stored procedures. Which TWO steps should the company take as part of the migration? (Choose two.)

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema and stored procedures to PostgreSQL-compatible format.. Option B is correct because the AWS Schema Conversion Tool (SCT) is specifically designed to convert Oracle schema objects, including stored procedures, to PostgreSQL-compatible format. Since the migration involves stored procedures, SCT is necessary to handle the syntax and logic differences between Oracle PL/SQL and PostgreSQL PL/pgSQL, ensuring the target database schema is ready for migration.

Answer

Set up AWS DMS ongoing replication to keep the target in sync after migration.

Answer

Use AWS DMS native Oracle to PostgreSQL endpoint to migrate data without schema conversion.

Answer

Enable RDS Proxy to reduce connection overhead during migration.

Question 7

Arrange the steps to enable automated backups for an Amazon RDS for PostgreSQL DB instance in the correct order.

Question 8

Arrange the steps to configure a read replica for an Amazon RDS for PostgreSQL DB instance in a different AWS Region in the correct order.

Question 9

Match each database engine to its default port number.

Question 10

Match each AWS security feature to its purpose for databases.

Question 11

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database has a large table with a BLOB column storing PDF files. Which migration approach minimizes downtime?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication.. Option B is correct because AWS DMS can perform ongoing replication to keep the target in sync during the full load, minimizing downtime. Option A is wrong because exporting and importing BLOBs can be time-consuming and cause significant downtime. Option C is wrong because direct backup restore requires a compatible format and may not support ongoing replication. Option D is wrong because disabling BLOB columns during migration is not practical for the application.

Answer

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

Answer

Use Oracle RMAN to back up the database and restore to RDS.

Answer

Export the table without the BLOB column, then import the BLOBs separately.

Question 12

A company wants to migrate a 2 TB PostgreSQL database from on-premises to Amazon Aurora PostgreSQL. The database has high write throughput and the migration must have minimal impact on source performance. Which solution is MOST appropriate?

Accepted Answer

Use pglogical to set up logical replication from the source to Aurora.. Option C is correct because using pglogical for logical replication allows near real-time replication with minimal overhead on the source. Option A is wrong because AWS DMS with ongoing replication can add some overhead to the source due to continuous fetching of changes. Option B is wrong because native PostgreSQL streaming replication requires the source to be a primary server and may cause performance impact. Option D is wrong because using a read replica reduces performance impact but requires a replica already set up.

Answer

Create a read replica of the on-premises database and promote it to Aurora.

Answer

Use AWS DMS with ongoing replication from the source to Aurora.

Answer

Set up native PostgreSQL streaming replication from on-premises to Aurora.

Question 13

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database uses InnoDB tables and is 500 GB in size. The migration must be completed within a 2-hour maintenance window. Which approach is MOST likely to meet the requirement?

Accepted Answer

Use mysqldump to export the database and then import it into RDS.. Option A is correct because using mysqldump with the --single-transaction flag exports a consistent snapshot without locking tables, and the data can be imported into RDS within the window if network bandwidth is sufficient. Option B is wrong because importing a physical backup from an on-premises database to RDS is not straightforward; RDS does not support backup file import directly. Option C is wrong because AWS DMS requires initial load and may not complete within 2 hours for 500 GB. Option D is wrong because creating a read replica requires the source to be an RDS instance, not on-premises.

Answer

Create a read replica of the on-premises database and promote it to RDS.

Answer

Use AWS DMS with a full load task.

Answer

Take a physical backup of the data directory and copy it to RDS.

Question 14

A company is migrating a 1 TB SQL Server database from on-premises to Amazon RDS for SQL Server. The database has a large table with a LOB column. The network bandwidth between the on-premises data center and AWS is limited to 50 Mbps. The migration must be completed within a week. Which approach should the company use?

Accepted Answer

Use AWS DMS with compression enabled.. Option D is correct because AWS DMS can compress data during transfer, reducing the amount of data sent over the network, and can complete within a week even with a 50 Mbps connection. Option A is wrong because SQL Server native backup and restore requires the backup file to be transferred over the network, which may take too long with 50 Mbps. Option B is wrong because BCP export/import also transfers the entire data over the network. Option C is wrong because creating a read replica is not possible from on-premises.

Answer

Use BCP to export the LOB table to flat files and then import to RDS.

Answer

Use SQL Server native backup and restore to RDS.

Answer

Create a read replica of the on-premises database and promote it.

Question 15

A company is migrating an on-premises MongoDB database to Amazon DocumentDB. The migration must be online with minimal downtime. The source MongoDB is version 4.0 and uses replica sets. Which tool should the company use?

Accepted Answer

Use AWS DMS with MongoDB as source and DocumentDB as target.. Option B is correct because AWS DMS supports MongoDB as a source and DocumentDB as a target, and can perform ongoing replication for minimal downtime. Option A is wrong because mongodump/mongorestore is a logical dump that requires downtime for a consistent snapshot. Option C is wrong because MongoDB Compass is a GUI tool and does not support ongoing replication to DocumentDB. Option D is wrong because creating a read replica from MongoDB to DocumentDB is not supported.

Answer

Use MongoDB Compass to export data and import into DocumentDB.

Answer

Use mongodump and mongorestore.

Answer

Create a read replica of the MongoDB replica set and promote to DocumentDB.