DBS-C01 Deployment and Migration Practice Test 22 — 15 Questions

Question 1

Refer to the exhibit. A database administrator has this IAM policy attached to their user. They attempt to delete the database instance 'prod-mydb' but receive an 'AccessDenied' error. Why?

Accepted Answer

The Deny statement explicitly denies deletion of any instance with an identifier starting with 'prod-'.. Option C is correct because the Deny statement explicitly denies deletion of any DB instance with identifier starting with 'prod-', and Deny takes precedence over Allow. Option A is wrong because the policy allows deletion for non-prod instances. Option B is wrong because the resource ARN is correct for prod-mydb. Option D is wrong because the error is not due to missing DescribeDBInstances.

Answer

The policy does not allow the rds:DeleteDBInstance action for any resource.

Answer

The resource ARN in the Deny statement does not match the instance.

Answer

The user does not have permission to describe the DB instance.

Question 2

A company is running a production PostgreSQL database on an EC2 instance (db.m5.xlarge) with 500 GB of gp2 EBS storage. The database is used by a customer-facing application that requires low latency. The company plans to migrate this database to Amazon RDS for PostgreSQL with minimal downtime. The current database has a high write load with frequent updates and deletes, and the table sizes are growing. The company also wants to enable Multi-AZ for high availability and use read replicas for reporting workloads. During migration planning, they discover that the source database has several large unlogged tables and uses custom PostgreSQL extensions that are not available in RDS. Which migration strategy should the company use to minimize downtime and meet all requirements?

Accepted Answer

Use AWS DMS with ongoing replication, convert unlogged tables to logged tables, and migrate custom extensions using AWS SCT.. Option B is correct because AWS DMS can migrate data while converting the unlogged tables to logged tables (since DMS replicates changes) and can handle custom extensions by focusing on schema conversion. Option A is wrong because unlogged tables cannot be replicated via streaming replication. Option C is wrong because native pg_dump/pg_restore is offline and would cause downtime. Option D is wrong because S3 copy is not a supported migration method.

Answer

Use pg_dump to export the database and pg_restore to import into RDS, then set up read replicas.

Answer

Copy the database files to Amazon S3, then use the rdsadmin.rdsadmin_restore_from_s3 procedure to restore to RDS.

Answer

Set up PostgreSQL streaming replication from the EC2 instance to an RDS read replica, then promote the replica.

Question 3

A company is migrating a 2 TB Oracle database to Amazon Aurora PostgreSQL. They need to minimize downtime and ensure data consistency. Which migration strategy should they use?

Accepted Answer

Use AWS DMS with ongoing replication (change data capture) from Oracle to Aurora.. Option C is correct because AWS DMS with ongoing replication allows continuous data sync, minimizing downtime. Option A is wrong because exporting to CSV and importing is manual and not suitable for minimal downtime. Option B is wrong because native PostgreSQL pg_dump/pg_restore requires downtime. Option D is wrong because S3 transfer is for file-based data, not live databases.

Answer

Use AWS DMS with full load only, then cut over during a maintenance window.

Answer

Export the database to Amazon S3 using Oracle Data Pump, then import into Aurora.

Answer

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

Question 4

A company wants to migrate an on-premises MySQL database to Amazon RDS for MySQL. The database is 500 GB and experiences heavy write traffic. They need to minimize downtime and ensure no data loss. Which approach should they take?

Accepted Answer

Set up MySQL replication from the on-premises database to RDS, then promote the RDS instance when ready.. Option D is correct because setting up MySQL replication from on-premises to RDS allows near-zero downtime migration. Option A is wrong because a dump and reload requires the source to be read-only. Option B is wrong because AWS DMS with full load only does not capture ongoing changes. Option C is wrong because creating a read replica from on-premises is not supported; RDS read replicas are only for RDS instances.

Answer

Use AWS DMS with a full load task, then cut over the application to RDS.

Answer

Create an RDS read replica of the on-premises database, then promote it to a standalone instance.

Answer

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

Question 5

A company is migrating a 1 TB SQL Server database to Amazon RDS for SQL Server. They want to use the native backup and restore feature. What must they do first?

Accepted Answer

Upload the backup file to an Amazon S3 bucket.. Option A is correct because native backup/restore to RDS requires storing backups in an S3 bucket. Option B is wrong because RDS does not support direct FTP. Option C is wrong because the backup file must be in S3, not uploaded to RDS directly. Option D is wrong because the backup file should be in S3, not stored on the RDS instance.

Answer

Store the backup file on an EBS volume attached to the RDS instance.

Answer

Use FTP to transfer the backup file directly to the RDS instance.

Answer

Use the AWS Management Console to upload the backup file to the RDS instance.

Question 6

A company is migrating a MongoDB database to Amazon DocumentDB. They have a 200 GB database and need to minimize downtime. Which migration approach is most appropriate?

Accepted Answer

Set up MongoDB replication from the source to DocumentDB, then promote DocumentDB.. Option B is correct because DocumentDB supports MongoDB 3.6/4.0 replication protocol, allowing near-zero downtime via native replication. Option A is wrong because mongodump/mongorestore requires downtime. Option C is wrong because AWS DMS does not support MongoDB as a source. Option D is wrong because EBS snapshots are not applicable to DocumentDB.

Answer

Take an EBS snapshot of the MongoDB volume and restore it to DocumentDB.

Answer

Export the database using mongodump and import using mongorestore into DocumentDB.

Answer

Use AWS DMS to migrate data from MongoDB to DocumentDB.

Question 7

A company is planning to migrate a 5 TB Oracle data warehouse to Amazon Redshift. They need to transform the data during migration. Which AWS service should they use to perform the transformation?

Accepted Answer

AWS Glue to perform extract, transform, and load (ETL) jobs.. Option D is correct because AWS Glue is a serverless ETL service that can perform transformations. Option A is wrong because AWS DMS is for database migration with minimal transformation. Option B is wrong because Kinesis is for real-time streaming data. Option C is wrong because Athena is a query service, not an ETL tool.

Answer

Amazon Kinesis Data Analytics for real-time transformation.

Answer

Amazon Athena to query the source data and write results to Redshift.

Answer

AWS Database Migration Service (DMS) with transformation rules.

Question 8

A company is migrating a PostgreSQL database to Amazon RDS for PostgreSQL. They want to automate the deployment of the RDS instance using infrastructure as code. Which AWS service should they use?

Accepted Answer

AWS CloudFormation.. AWS CloudFormation is the correct service for automating the deployment of an RDS for PostgreSQL instance using infrastructure as code. It allows you to define the entire RDS instance configuration—including DB instance class, storage, backup retention, and security groups—in a declarative JSON or YAML template, which can be version-controlled and reused for consistent, repeatable deployments.

Answer

Amazon EC2 Auto Scaling.

Answer

AWS Management Console.

Answer

AWS Command Line Interface (CLI).

Question 9

A company is migrating a 100 GB Oracle database to Amazon RDS for Oracle. They want to use AWS DMS. The source database is in a different AWS account. What is required to allow DMS to connect to the source?

Accepted Answer

Establish VPC peering or VPN between the source and target VPCs, and configure security group rules.. Option C is correct because DMS needs network connectivity via VPC peering or VPN, and the source security group must allow DMS. Option A is wrong because VPC endpoints are not needed for DMS to source. Option B is wrong because DMS does not use an S3 endpoint for source connectivity. Option D is wrong because DMS does not use an IAM role for database connectivity; it uses database credentials.

Answer

Assign an IAM role to the source database to allow DMS access.

Answer

Configure an S3 VPC gateway endpoint for the source VPC.

Answer

Create a VPC endpoint for DMS in the source account.

Question 10

A company is migrating a 3 TB MySQL database to Amazon Aurora MySQL. They need to validate data consistency after migration. Which approach should they use?

Accepted Answer

Use AWS DMS data validation feature.. Option C is correct because AWS DMS provides data validation to compare source and target data. Option A is wrong because comparing row counts is insufficient for consistency. Option B is wrong because checksums on all columns would be very expensive and time-consuming. Option D is wrong because querying random rows is not comprehensive.

Answer

Compare row counts between source and target tables.

Answer

Run random SELECT queries on a subset of rows to compare values.

Answer

Compute MD5 checksums of the entire dataset in both databases.

Question 11

A company is migrating an on-premises DynamoDB table to Amazon DynamoDB in another AWS region. What is the most efficient method to migrate the data?

Accepted Answer

Use DynamoDB global tables to replicate data across regions.. Option A is correct because DynamoDB global tables provide multi-region replication with minimal effort. Option B is wrong because AWS DMS does not support DynamoDB as a source. Option C is wrong because S3 export/import is an additional step. Option D is wrong because setting up replication manually is less efficient than using global tables.

Answer

Export the table to S3 using AWS Data Pipeline, then import into DynamoDB in the target region.

Answer

Set up DynamoDB Streams and write a custom consumer to replicate data to the target region.

Answer

Use AWS DMS to replicate data from on-premises to DynamoDB.

Question 12

A company is migrating a MySQL database to Amazon RDS for MySQL. They want to use AWS DMS for continuous replication. Which TWO prerequisites must be met before starting the migration?

Accepted Answer

Enable binary logging (binlog) on the source MySQL database.. Options A and B are correct. DMS requires binary logging to be enabled on the source for CDC, and the replication instance must be in a VPC with network access. Option C is wrong because the source database does not need to be in a VPC. Option D is wrong because DMS supports continuous replication without requiring read-only mode. Option E is wrong because S3 is not required for DMS.

Answer

Set the source database to read-only mode during migration.

Answer

Place the source database in a VPC.

Answer

Create an S3 bucket to store the migration logs.

Question 13

A company is migrating a 500 GB Oracle database to Amazon RDS for Oracle. They need to validate the migration and ensure data consistency. Which TWO methods should they use?

Accepted Answer

Use AWS DMS data validation feature.. Options B and D are correct. AWS DMS provides data validation, and comparing row counts and checksums can verify consistency. Option A is wrong because CloudWatch does not validate data. Option C is wrong because querying random rows is not comprehensive. Option E is wrong because S3 inventory is unrelated to database consistency.

Answer

Use Amazon S3 inventory reports on the exported data.

Answer

Run random SELECT queries on a subset of tables.

Answer

Use Amazon CloudWatch Logs to compare database logs.

Question 14

A company is migrating a PostgreSQL database to Amazon Aurora PostgreSQL. They want to use the AWS DMS for the migration. Which THREE resources need to be created in the AWS account?

Accepted Answer

DMS target endpoint pointing to Aurora PostgreSQL.. Options A, B, and D are correct. DMS requires a replication instance, source endpoint, and target endpoint. Option C is wrong because a CloudFormation stack is not required. Option E is wrong because a load balancer is not needed for DMS.

Answer

Application Load Balancer for the replication instance.

Answer

AWS CloudFormation stack to provision resources.

Question 15

A company is migrating a 2 TB Oracle database running on an on-premises Linux server to Amazon RDS for Oracle. The migration must have minimal downtime and must be fully reversible if any issues arise. The DBA has configured AWS DMS with a full load and ongoing replication task. The full load completes successfully, and CDC is replicating changes. During the cutover window, the DBA stops the source database and promotes the target RDS instance. However, after cutover, the application team reports that some recent transactions are missing from the target database. The DBA confirms that the DMS task showed a 'healthy' status before stopping. Which action should the DBA take to resolve the issue and prevent recurrence?

Accepted Answer

Before stopping the source database, run the 'Stop task' command with the '--apply-immediately' option to ensure all cached changes are written to the target.. Option B is correct. In a DMS migration, the final step should be to capture remaining changes after stopping the source database. This is done by running the 'Stop task' command with the '--apply-immediately' flag or by using the 'Last Stop' command in the console. Option A is wrong because increasing the replication instance size does not address missing transactions. Option C is wrong because restarting the task does not capture the missed transactions; they were already lost. Option D is wrong because rebuilding the migration from scratch is time-consuming and does not address the root cause.

Answer

Rebuild the entire migration using a native Oracle export/import tool.

Answer

Increase the replication instance size to improve throughput.

Answer

Restart the DMS task from the beginning to recapture the missing data.

DBS-C01 Deployment and Migration Practice Test 22 — 15 Questions

Exhibit

DBS-C01 Deployment and Migration Practice Test 22 — 15 Questions

Exhibit