DBS-C01 Deployment and Migration Practice Test 19 — 15 Questions

Question 1

A company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. They want to use AWS DMS for continuous replication. However, the migration is taking longer than expected due to LOB columns. What optimization should be applied?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Set MaxLobSize to a value like 64 KB to limit inline LOB transfer.. Setting MaxLobSize to a value like 64 KB instructs AWS DMS to treat LOBs smaller than that threshold as inline data, which is transferred more efficiently in the batch stream. This avoids the performance penalty of using FullLobMode, which transfers each LOB individually and can dramatically slow down continuous replication for large tables with many LOB columns.

Answer

Use AWS SCT to compress LOBs.

Answer

Enable FullLobMode to transfer all LOBs.

Answer

Increase the number of DMS tasks.

Question 2

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. They need to validate that the schema is compatible. Which AWS service should they use?

Accepted Answer

AWS Schema Conversion Tool (SCT). The AWS Schema Conversion Tool (SCT) is designed specifically to assess and convert database schemas from one engine to another, including on-premises MySQL to Amazon RDS for MySQL. It analyzes the source schema for compatibility issues, identifies unsupported features or deprecated syntax, and generates a detailed assessment report. This makes it the correct choice for validating schema compatibility before migration.

Answer

Amazon Inspector

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AWS Database Migration Service (DMS)

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AWS Trusted Advisor

Question 3

A company is migrating a PostgreSQL database to Amazon Aurora PostgreSQL. They have set up AWS DMS with change data capture (CDC). However, after the initial load, the CDC replication is experiencing high latency. What is the MOST likely cause?

Accepted Answer

The source database has large transactions that are not committed quickly.. Large uncommitted transactions on the source database cause DMS CDC to buffer changes until the transaction commits, leading to high latency. DMS must wait for the commit record before applying changes to the target Aurora instance, and during this time, CDC replication stalls, accumulating a backlog of changes.

Answer

The target Aurora instance has insufficient storage.

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The DMS instance is using an older engine version.

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The network bandwidth is too low.

Question 4

A company is migrating a 5 TB SQL Server database to Amazon RDS for SQL Server using AWS DMS. They are using Full LOB mode. The migration is failing with an error about memory allocation. What should they do to resolve this?

Accepted Answer

Increase the DMS replication instance class.. The memory allocation error in AWS DMS Full LOB mode occurs when the replication instance lacks sufficient memory to buffer LOB data. Increasing the replication instance class (option B) directly provides more memory, resolving the issue. Decreasing MaxLobSize (A) would truncate data, not fix allocation. Splitting the task (C) does not increase memory per instance. Enabling BatchApply (D) improves commit efficiency but does not address memory allocation for LOBs. Therefore, B is correct.

Answer

Decrease the MaxLobSize setting.

Answer

Split the migration into multiple DMS tasks.

Answer

Enable BatchApply on the DMS task.

Question 5

A company is migrating a MySQL database from on-premises to Amazon RDS for MySQL. They want to use native MySQL replication to minimize downtime. Which configuration is required in the on-premises MySQL server?

Accepted Answer

Enable binary logging with binlog_format = ROW. Native MySQL replication requires binary logging on the source server to capture all changes. Setting binlog_format = ROW ensures that row-level changes are logged, which is the recommended format for cross-version replication and is required by Amazon RDS for MySQL to support replication from an external source. Without binary logging enabled, the on-premises MySQL server cannot act as a replication master.

Answer

Enable the slow query log

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Enable the audit log

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Enable the error log

Question 6

A company is migrating an on-premises MongoDB database to Amazon DocumentDB. They need to ensure that the migration is completed with minimal downtime and that data remains consistent. Which tool should they use?

Accepted Answer

Use AWS DMS with MongoDB as source and DocumentDB as target. AWS DMS supports continuous change data capture (CDC) from MongoDB to Amazon DocumentDB, enabling near-zero downtime migration by replicating ongoing changes after the initial full load. This ensures data consistency without requiring application downtime, unlike batch export/import methods.

Answer

Use mongoexport and mongoimport

Answer

Export data to Amazon S3 and load into DocumentDB

Answer

Use MongoDB Atlas Live Migration

Question 7

A company wants to deploy an Amazon RDS for MySQL database for a new application. The database must be highly available with automatic failover. Which configuration should they choose?

Accepted Answer

Deploy a Multi-AZ instance with a standby replica. A Multi-AZ deployment for Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In the event of a failure, Amazon RDS automatically fails over to the standby, providing high availability without manual intervention. This configuration meets the requirement for automatic failover and high availability.

Answer

Deploy a single-AZ instance with automated backups

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Deploy a cross-region replica

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Deploy a single-AZ instance with a read replica

Question 8

A company is migrating a 3 TB PostgreSQL database from on-premises to Amazon Aurora PostgreSQL. They need to minimize downtime and ensure that the migration is completed within a maintenance window. Which approach should they use?

Accepted Answer

Use AWS DMS with full load and ongoing replication (CDC). AWS DMS with full load and ongoing replication (CDC) is the correct approach because it allows you to perform an initial full load of the 3 TB database while continuously capturing changes from the source PostgreSQL using logical replication (via the pglogical extension or native slot-based replication). This minimizes downtime by keeping the target Aurora PostgreSQL nearly synchronized, and you can switch over during a maintenance window with only a brief outage to apply any final lag.

Answer

Use AWS SCT to convert the schema and then migrate data

Answer

Use pg_dump to export the database and pg_restore to import into Aurora

Answer

Take a file system snapshot and restore to Aurora

Question 9

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The migration uses AWS DMS with ongoing replication (CDC). Which TWO tasks must be completed before starting the migration?

Accepted Answer

Enable supplemental logging in the Oracle source database. Option A is correct because AWS DMS requires supplemental logging enabled on the Oracle source database so that redo/archive log records contain the additional column-level information needed for ongoing replication (CDC) to capture INSERT, UPDATE, and DELETE changes accurately. Option B is correct because DMS needs a dedicated Oracle user account granted the required privileges (for example, SELECT on the tables, plus LogMiner-related privileges such as SELECT on V_$LOGMNR_*, EXECUTE on DBMS_LOGMNR, and SELECT ANY TRANSACTION) to read the source data and mine the redo logs during CDC. Option C is wrong because the scenario explicitly requires ongoing replication, so full load only without CDC would not meet the requirement. Option D is wrong because disabling archive logging would break CDC, since DMS relies on archived redo logs for change capture. Option E is wrong because binary logging is a MySQL/MariaDB concept, not an Oracle one; Oracle uses supplemental logging and LogMiner instead.

Answer

Configure DMS to use only full load without CDC

Answer

Disable archive logging on the Oracle source

Answer

Enable binary logging on the Oracle source

Question 10

A company is migrating a 2 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL with minimal downtime. The database is continuously updated. Which migration strategy should be used?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication from an on-premises source.. AWS DMS supports ongoing replication (change data capture, CDC) from an on-premises PostgreSQL source to Amazon RDS for PostgreSQL, enabling minimal downtime migration. The 2 TB size is well within DMS's capabilities, and CDC captures incremental changes after the full load, allowing near-zero downtime cutover.

Answer

Use AWS Schema Conversion Tool (SCT) and AWS Snowball to transfer data.

Answer

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

Answer

Use pg_dump and pg_restore during a maintenance window.

Question 11

A company is migrating a 500 GB Oracle database to Amazon Aurora PostgreSQL. They need to convert the schema and migrate the data. The application uses Oracle-specific features like hierarchical queries and stored procedures. Which combination of services should they use?

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema and AWS Database Migration Service (DMS) to migrate the data.. AWS SCT converts Oracle-specific schema objects (including hierarchical queries and stored procedures) to PostgreSQL-compatible code, while AWS DMS handles the ongoing data migration with minimal downtime. This combination is the standard AWS approach for heterogeneous database migrations, as SCT addresses schema conversion and DMS handles data transfer.

Answer

Use AWS Snowball Edge to transfer the database files and then use SCT to convert the schema.

Answer

Use AWS Database Migration Service (DMS) with the Oracle as source and Aurora PostgreSQL as target.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema and then manually export/import data.

Question 12

A company is deploying a new web application and needs a fully managed relational database with automatic failover and read replicas. Which AWS service should they choose?

Accepted Answer

Amazon RDS for MySQL with Multi-AZ deployment. Amazon RDS for MySQL with Multi-AZ deployment provides a fully managed relational database service that automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In the event of a failure, Amazon RDS automatically fails over to the standby, ensuring high availability. Additionally, RDS for MySQL supports read replicas for offloading read traffic, which meets the requirement for both automatic failover and read replicas.

Answer

Amazon DynamoDB

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Amazon EC2 with self-managed MySQL

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Amazon Redshift

Question 13

A company is deploying a new application that requires low-latency reads from a relational database across multiple AWS Regions. The application is read-heavy and can tolerate eventual consistency. Which deployment option meets these requirements?

Accepted Answer

Deploy Amazon Aurora Global Database with a primary Region and read replicas in secondary Regions.. Amazon Aurora Global Database is designed for low-latency global reads and disaster recovery, allowing up to five secondary Regions with dedicated read replicas that replicate data with a typical latency of under one second. This meets the requirement for low-latency reads across multiple Regions while tolerating eventual consistency, as reads from secondary Regions are eventually consistent with the primary.

Answer

Deploy Amazon RDS for PostgreSQL with Multi-AZ and read replicas in the same Region.

Answer

Deploy a single Amazon RDS for MySQL instance with cross-Region read replicas.

Answer

Deploy Amazon DynamoDB Global Tables in multiple Regions.

Question 14

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?

Accepted Answer

Use AWS Database Migration Service with full load and change data capture (CDC).. AWS Database Migration Service (DMS) with full load and change data capture (CDC) is the correct approach because it minimizes downtime by performing an initial full load of the Oracle database and then continuously replicating ongoing changes until the cutover, allowing the migration to complete within a short maintenance window. Unlike Oracle Data Pump, which requires the source database to be offline during export/import, DMS with CDC keeps the source operational and only requires a brief outage at final cutover.

Answer

Use AWS Snowball to transfer the database files to AWS and then restore to RDS.

Answer

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

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema and then use DMS for data migration.

Question 15

A company wants to deploy a MySQL database that automatically scales read capacity based on traffic without manual intervention. Which AWS database offering should they use?

Accepted Answer

Amazon Aurora with Auto Scaling for read replicas. Amazon Aurora with Auto Scaling for read replicas is correct because it automatically adjusts the number of Aurora Replicas based on changes in read workload, scaling read capacity without manual intervention. Aurora's Auto Scaling monitors the average CPU utilization or connections of the reader fleet and adds or removes replicas to maintain a target metric, providing seamless read scaling for MySQL-compatible databases.

Answer

Amazon DynamoDB with auto scaling

Answer

Amazon RDS for MySQL with Multi-AZ deployment

Answer

Amazon RDS for MySQL with a Single-AZ deployment