DBS-C01 Deployment and Migration Practice Test 4 — 15 Questions

Question 1

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 error about memory allocation when using Full LOB mode in AWS DMS indicates that the replication instance does not have sufficient memory to buffer the LOB data during migration. Increasing the replication instance class provides more memory, allowing DMS to handle the LOB data without hitting allocation limits. This is the direct and recommended fix for memory-related failures in DMS LOB migrations.

Answer

Decrease the MaxLobSize setting.

Answer

Split the migration into multiple DMS tasks.

Answer

Enable BatchApply on the DMS task.

Question 2

Which TWO of the following are required when migrating an on-premises Oracle database to Amazon RDS for Oracle using AWS DMS with change data capture (CDC)? (Select TWO.)

Accepted Answer

Use AWS SCT to assess schema compatibility.. For Oracle CDC, DMS requires supplemental logging to capture changes, and an SCT assessment is needed for schema compatibility. Full backup is not required, and native replication is not used. DMS creates target tables automatically.

Answer

Create a full backup of the source database.

Answer

Set up Oracle Data Guard for replication.

Answer

Manually create target tables in RDS.

Question 3

Which THREE factors should be considered when choosing between a homogeneous migration and a heterogeneous migration to Amazon RDS? (Select THREE.)

Accepted Answer

Performance requirements of the target database.. Option B is correct because the performance requirements of the target database directly influence the choice between homogeneous and heterogeneous migrations. In a homogeneous migration (e.g., MySQL to RDS MySQL), the target engine is identical, so performance tuning is minimal. In a heterogeneous migration (e.g., Oracle to RDS PostgreSQL), the target engine has different query optimizers, indexing strategies, and concurrency models, which may require re-architecting to meet performance SLAs. AWS DMS Schema Conversion Tool (SCT) can help assess performance impacts, but the target engine's inherent performance characteristics must be evaluated upfront.

Answer

Network latency between source and target.

Answer

Amount of application code changes needed.

Question 4

Which TWO AWS services can be used together to migrate an on-premises MySQL database to Amazon Aurora MySQL with minimal downtime? (Select TWO.)

Accepted Answer

AWS Schema Conversion Tool (SCT). AWS Database Migration Service (DMS) can perform continuous replication from an on-premises MySQL source to an Amazon Aurora MySQL target using change data capture (CDC), enabling near-zero downtime. The AWS Schema Conversion Tool (SCT) is used to assess and convert the source schema, including any incompatible objects, to ensure the Aurora target is ready for migration. Together, SCT handles schema transformation while DMS handles the ongoing data replication.

Answer

Amazon Route 53

Answer

AWS CloudFormation

Answer

AWS Global Accelerator

Question 5

A company is migrating a 2 TB on-premises Oracle database to Amazon RDS for Oracle. The migration must have minimal downtime and support ongoing replication. Which AWS service should be used to accomplish this?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct choice because it supports homogeneous migrations (Oracle to Oracle) with minimal downtime through ongoing replication using change data capture (CDC). It can handle a 2 TB database by using a large enough replication instance and enabling task logging for validation, ensuring data consistency during the migration.

Answer

AWS Schema Conversion Tool (AWS SCT)

Answer

AWS DataSync

Answer

AWS Glue

Question 6

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

Answer

Enable the audit log

Answer

Enable the error log

Question 7

A team is deploying a new Amazon Aurora MySQL database and needs to load 5 TB of data from an existing Amazon RDS for MySQL database with minimal downtime. The data is stored in InnoDB tables. Which approach is MOST efficient?

Accepted Answer

Create an Aurora read replica from the RDS for MySQL instance using binlog replication. Option D is correct because creating an Aurora read replica from an RDS for MySQL instance using binlog replication allows the Aurora cluster to synchronize with the source database in near real-time. Once the replica lag reaches zero, you can promote the Aurora cluster to become the primary database, achieving minimal downtime. This approach leverages the native MySQL binlog replication, which is efficient for large datasets like 5 TB and avoids the overhead of exporting or snapshotting the entire database.

Answer

Take a snapshot of the RDS for MySQL instance and restore to Aurora

Answer

Use AWS DMS with full load and ongoing replication

Answer

Use mysqldump to export the database and import into Aurora

Question 8

A company is migrating a 500 GB SQL Server database to Amazon RDS for SQL Server. They need to minimize downtime and support ongoing changes during migration. Which approach should they take?

Accepted Answer

Use AWS DMS with full load and change data capture (CDC). AWS DMS with full load and change data capture (CDC) is the correct approach because it allows the initial 500 GB data load to be migrated while continuously replicating ongoing changes from the source SQL Server database to Amazon RDS for SQL Server. This minimizes downtime by enabling a cutover only after the target is fully synchronized, and it supports ongoing changes during migration without requiring the source database to be taken offline.

Answer

Use native SQL Server backup and restore to RDS

Answer

Set up a Direct Connect connection and use log shipping

Answer

Use SQL Server Integration Services (SSIS) to replicate data

Question 9

A company is deploying a new Amazon RDS for PostgreSQL database. The database will be used by an application that requires read-after-write consistency and low latency. Which deployment configuration is MOST suitable?

Accepted Answer

Deploy with one or more read replicas in the same region. Multi-AZ deployment with synchronous standby provides high availability and data durability, but does not improve read performance. Read replicas (Option B) improve read scalability but may have eventual consistency. Option C (single-AZ) lacks HA. Option D (cross-region) is for DR.

Answer

Deploy with cross-region replicas

Answer

Deploy as a single-AZ instance with increased instance size

Answer

Deploy as Multi-AZ with a synchronous standby

Question 10

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 11

A company is deploying a new Amazon DynamoDB table with global tables for a multi-region application. The application requires strongly consistent reads in the primary region and eventual consistency in secondary regions. Which write strategy should they use?

Accepted Answer

Use DynamoDB global tables with last writer wins (LWW) conflict resolution. DynamoDB global tables use last writer wins (LWW) for conflict resolution, which is eventually consistent. Strongly consistent reads are supported only in the region where the write occurred (primary region). Option B (conditional writes) does not change consistency. Option C (transactions) are not global. Option D (DynamoDB Streams) does not affect consistency.

Answer

Use conditional writes to ensure consistency

Answer

Use DynamoDB Streams to replicate writes to secondary regions

Answer

Use DynamoDB transactions across regions

Question 12

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. Multi-AZ deployment provides automatic failover to a standby in a different AZ. Option A (single-AZ) does not provide HA. Option C (read replicas) do not provide automatic failover. Option D (cross-region) is for DR, not HA.

Answer

Deploy a single-AZ instance with automated backups

Answer

Deploy a cross-region replica

Answer

Deploy a single-AZ instance with a read replica

Question 13

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 14

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 to be enabled on the Oracle source database for ongoing replication (CDC). Supplemental logging ensures that the redo logs contain sufficient information (e.g., primary key, unique key, or all column values) to reconstruct the changes for DMS to capture and apply to the target. Without it, DMS cannot generate the necessary log-based change data for CDC.

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 15

A company is deploying a new Amazon DynamoDB table with on-demand capacity. The table will store session data for a web application. Which THREE features should be enabled to improve performance and durability?

Accepted Answer

Auto scaling. Auto scaling is correct because DynamoDB on-demand capacity automatically scales throughput based on traffic patterns, eliminating the need for manual capacity management. However, the question asks for features to improve performance and durability, and auto scaling is not applicable to on-demand tables (it is for provisioned mode). For on-demand, throughput adjusts instantly, so auto scaling is irrelevant and should not be selected. The correct features for performance and durability are TTL (to automatically expire old session data, reducing storage costs and improving query performance), DAX (to provide in-memory caching for microsecond read latency), and PITR (to protect against accidental writes or deletes by enabling continuous backups).

Answer

Time to Live (TTL)

Answer

Global tables