DBS-C01 Deployment and Migration Practice Test 16 — 15 Questions

Question 1

A company is migrating a 200 GB PostgreSQL database to Amazon Aurora PostgreSQL. They want to use the AWS DMS console to create a migration task. The source database is in a VPC and the target Aurora cluster is in the same VPC. The DMS replication instance is also in the same VPC. The source database is publicly accessible. What additional configuration is required to enable connectivity between DMS and the source database?

Accepted Answer

Configure the source database's security group to allow inbound traffic from the DMS replication instance's security group.. Option D is correct because even though the source is publicly accessible, DMS is in a VPC and cannot directly access public IPs unless the VPC has an internet gateway and the route table allows it. The security group of the source must allow inbound traffic from the DMS replication instance's security group. Option A is wrong because DMS does not require a VPC endpoint for source connectivity. Option B is wrong because the replication instance subnet group is already set. Option C is wrong because the source database should not be in public subnet; it can be private with proper routing.

Answer

Associate the DMS replication instance with a subnet group that includes public subnets.

Answer

Place the source database in the same public subnet as the DMS replication instance.

Answer

Create a VPC endpoint for the source database service.

Question 2

A company is migrating a 3 TB Oracle database to Amazon RDS for Oracle. They want to use Oracle Data Pump to export the data and then import it into RDS. What is the most efficient way to transfer the dump files to AWS?

Accepted Answer

Upload the dump files to Amazon S3 and then import them into RDS for Oracle using Oracle Data Pump.. Option C is correct because uploading the dump files to Amazon S3 and then using the Oracle Data Pump import from S3 (via UTL_FILE or direct read) is efficient and scalable. Option A is wrong because transferring over VPN/Direct Connect can be slow for large files. Option B is wrong because AWS Snowball is designed for very large data transfers (petabytes) and may be overkill for 3 TB, plus it adds logistics time. Option D is wrong because AWS DMS is a separate service for migration, not for transferring dump files.

Answer

Use AWS Snowball to physically ship the dump files to AWS.

Answer

Use AWS DMS to migrate the data directly from Oracle to RDS for Oracle.

Answer

Transfer the dump files over a VPN connection to an EC2 instance and then copy to RDS.

Question 3

Which TWO steps are required when migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server using AWS DMS with ongoing replication?

Accepted Answer

Enable MS-CDC (change data capture) on the source database.. Option B is correct because DMS requires full recovery model to capture all transactions. Option E is correct because DMS uses MS-CDC (change data capture) to capture ongoing changes. Option A is wrong because DMS does not require MS-Replication; it uses its own CDC mechanism. Option C is wrong because DMS uses a replication instance, not an EC2 instance agent. Option D is wrong because cross-VPC peering is not required; DMS can connect via VPN/Direct Connect.

Answer

Create a VPC peering connection between the on-premises network and the DMS VPC.

Answer

Install the DMS agent on the source SQL Server instance.

Answer

Configure MS-Replication on the source database.

Question 4

Which THREE factors should be considered when choosing between a native database migration tool (e.g., pg_dump) and AWS DMS for migrating a database to Amazon RDS? (Choose three.)

Accepted Answer

Downtime tolerance during migration. Option A is correct because native tools like pg_dump require downtime for the entire export/import. Option D is correct because native tools do not support ongoing replication; DMS does. Option E is correct because native tools can be faster for full load of large databases. Option B is wrong because DMS supports cross-region migrations. Option C is wrong because DMS supports complex transformations.

Answer

Whether the target database is in a different AWS region

Answer

Need to perform complex data transformations during migration

Question 5

Which TWO actions are recommended when deploying an Amazon RDS for MySQL instance in a production environment to ensure high availability and durability? (Choose two.)

Accepted Answer

Enable automated backups with a retention period of at least 7 days. Option A is correct because Multi-AZ provides automatic failover. Option D is correct because automated backups with a retention period enable point-in-time recovery. Option B is wrong because deletion protection is for accidental deletion, not high availability. Option C is wrong because performance insights are for monitoring, not HA. Option E is wrong because enhanced monitoring is for metrics, not HA.

Answer

Enable Enhanced Monitoring

Answer

Enable Performance Insights

Answer

Enable deletion protection

Question 6

An IAM policy is attached to a user who is deploying a new RDS instance. What is the effect of this policy on the user's ability to modify an existing production database instance with the identifier 'prod-mydb'?

Accepted Answer

The user cannot modify the production database instance because the Deny statement explicitly denies ModifyDBInstance on production databases.. Option B is correct because the Deny statement explicitly denies the ModifyDBInstance action on resources matching the ARN pattern for production databases. Since Deny overrides any Allow, the user cannot modify any production database. Option A is wrong because the user can still create and describe instances. Option C is wrong because the user cannot modify any production instances regardless of region. Option D is wrong because the user cannot modify any production instance, even if they are not the owner.

Answer

The user can modify the production database instance because the Allow statement grants full access to RDS actions.

Answer

The user can modify the production database instance if they use the AWS CLI instead of the console.

Answer

The user cannot modify any database instance because the Deny statement denies ModifyDBInstance on all resources.

Question 7

A company has an Aurora MySQL cluster with three instances. The current writer instance is 'mycluster-instance-1'. The company wants to failover to 'mycluster-instance-2' for maintenance. What is the most direct way to achieve this?

Accepted Answer

Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2. Option B is correct because you can failover to a specific reader instance by using the --target-db-instance-identifier parameter in the failover-db-cluster command. Option A is wrong because rebooting the writer will cause a failover but may choose any reader, not necessarily instance-2. Option C is wrong because you cannot directly promote a reader to writer; failover must be initiated. Option D is wrong because modifying the cluster does not trigger failover.

Answer

Change the cluster's endpoint to point to instance-2.

Answer

Modify 'mycluster-instance-2' to promote it to writer.

Answer

Reboot 'mycluster-instance-1' to trigger a failover.

Question 8

A company is deploying a MySQL RDS instance using this CloudFormation template. After deployment, they notice that the database is not automatically backed up at the scheduled time. What is the most likely cause?

Accepted Answer

The BackupRetentionPeriod must be greater than 0 to enable automated backups; however, it is set to 7, so this is not the issue. The actual cause might be that the DB instance is using a storage engine not supported for backups (e.g., MyISAM).. Option C is correct because to enable automated backups, the BackupRetentionPeriod must be greater than 0. In the snippet, it is set to 7, so backups should be enabled. However, automated backups are only supported for InnoDB storage engine; if the instance uses MyISAM, backups may fail. But the question asks for most likely cause; another common issue is that the backup window is too short or conflicts with maintenance, but the snippet shows valid windows. Option A is wrong because MultiAZ does not affect backups. Option B is wrong because storage type gp2 supports backups. Option D is wrong because the backup window is defined.

Answer

The storage type gp2 does not support automated backups.

Answer

The PreferredBackupWindow is not defined, so backups are disabled.

Answer

MultiAZ is enabled, which disables automated backups.

Question 9

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The database is 2 TB in size and has a sustained write rate of 50 MB/s. The migration must have minimal downtime. Which migration approach should be used?

Accepted Answer

Use AWS DMS with ongoing replication (change data capture). Option D is correct because AWS Database Migration Service (DMS) with ongoing replication allows minimal downtime by continuously replicating changes from the source to the target. Option A is wrong because AWS DMS with full load only does not support ongoing replication, leading to downtime. Option B is wrong because pg_dump/pg_restore is a logical backup tool that requires downtime during the dump and restore process. Option C is wrong because an RDS read replica can only be created from an existing RDS instance, not from on-premises.

Answer

Create an RDS read replica from the on-premises database

Answer

Use pg_dump and pg_restore

Answer

Use AWS DMS with a full-load task only

Question 10

A developer is migrating a self-managed MongoDB database to Amazon DocumentDB. The database contains 500 GB of data. What is the most efficient method to perform the initial data load?

Accepted Answer

Use mongodump and mongorestore. Option B is correct because mongodump and mongorestore are the standard tools for logical backup and restore in MongoDB, and they are compatible with DocumentDB. Option A is wrong because AWS DMS supports MongoDB as a source but is less efficient for large initial loads compared to native tools. Option C is wrong because creating a snapshot of a self-managed database is not applicable to DocumentDB. Option D is wrong because mongodump with the --out parameter does not load data into DocumentDB; it creates dump files.

Answer

Take a file system snapshot and restore to DocumentDB

Answer

Use AWS DMS with full load

Answer

Use mongodump with --out and then import using mongoimport

Question 11

A company has an Amazon RDS for MySQL database with Multi-AZ deployment. The database is experiencing high CPU utilization due to a reporting workload. The company wants to migrate to Amazon Aurora MySQL to improve performance and scalability. The migration must have minimal downtime. Which migration strategy meets these requirements?

Accepted Answer

Create an Aurora MySQL replica from the RDS MySQL instance and promote it. Option C is correct because creating an Aurora read replica from an RDS MySQL instance and then promoting it to a standalone Aurora cluster provides minimal downtime and leverages the built-in replication. Option A is wrong because taking a snapshot and restoring to Aurora requires downtime during the restore process. Option B is wrong because AWS DMS with full load plus CDC can achieve minimal downtime but is more complex and slower than using native replication. Option D is wrong because migrating to a larger RDS instance does not address the need to move to Aurora.

Answer

Take a snapshot of the RDS instance and restore it to an Aurora cluster

Answer

Migrate to a larger RDS MySQL instance to handle the workload

Answer

Use AWS DMS with full load and ongoing replication

Question 12

A company is migrating a 10 TB Oracle database to Amazon RDS for Oracle. The migration window is limited to 24 hours. The source database is running on-premises with a 500 Mbps network connection. Which migration approach should be used?

Accepted Answer

Use AWS DMS with full load and ongoing replication. Option A is correct because AWS DMS with ongoing replication can handle large data volumes and minimize downtime by continuously replicating changes. Option B is wrong because Oracle Data Pump is a manual export/import process that requires downtime and may not complete within 24 hours if the network is slow. Option C is wrong because the source is on-premises, not an EC2 instance, so a read replica cannot be created. Option D is wrong because taking a backup and restoring to RDS requires the backup to be transferred to S3 first, which may be time-consuming.

Answer

Create an RDS read replica from the on-premises database

Answer

Take a physical backup of the source database and restore to RDS

Answer

Use Oracle Data Pump to export and import the database

Question 13

A company is deploying a new application that requires a highly available DynamoDB table with eventual consistency. The table will be accessed from multiple AWS Regions. What is the most appropriate deployment strategy?

Accepted Answer

Use DynamoDB global tables. Option C is correct because DynamoDB global tables provide multi-region replication with eventual consistency, meeting the requirements. Option A is wrong because DynamoDB Accelerator (DAX) is a caching layer, not a multi-region solution. Option B is wrong because DynamoDB Streams can be used for cross-region replication but require custom code; global tables are the managed solution. Option D is wrong because DynamoDB auto scaling adjusts capacity, not replication.

Answer

Use DynamoDB auto scaling to handle regional traffic

Answer

Use DynamoDB Accelerator (DAX) to cache data across regions

Answer

Use DynamoDB Streams to replicate data to another region

Question 14

A company is migrating a 5 TB Microsoft SQL Server database to Amazon RDS for SQL Server. The migration must have minimal downtime. The source database is hosted on an EC2 instance. Which combination of steps should be taken?

Accepted Answer

Take a native backup of the source, upload to S3, and restore to RDS. Option B is correct because taking a native backup of the source database, uploading it to S3, and restoring to RDS is the most efficient method for large databases with minimal downtime. Option A is wrong because AWS DMS with ongoing replication is a viable option but may be slower for initial load. Option C is wrong because creating a read replica from an EC2-hosted database is not supported. Option D is wrong because using the Import Export wizard is manual and not suitable for large databases.

Answer

Use AWS DMS with full load and ongoing replication

Answer

Create an RDS read replica from the EC2-hosted database

Answer

Use the SQL Server Import and Export Wizard

Question 15

A company has a self-managed Redis cluster that needs to be migrated to Amazon ElastiCache for Redis. The cluster is 100 GB in size and has a high write throughput. The migration must have minimal downtime. Which steps should be taken?

Accepted Answer

Set up replication from the source to ElastiCache using Redis replication. Option D is correct because setting up replication from the on-premises Redis to ElastiCache using the replication features can achieve minimal downtime. Option A is wrong because AWS DMS does not support Redis as a source. Option B is wrong because taking a snapshot and restoring requires downtime during the restore process. Option C is wrong because the SAVE command is synchronous and can cause performance issues; BGSAVE is preferred.

Answer

Use AWS DMS to migrate the data with ongoing replication

Answer

Take a snapshot of the source and restore to ElastiCache

Answer

Use the SAVE command to create a dump, upload to S3, and import to ElastiCache