DBS-C01 Deployment and Migration Practice Test 10 — 15 Questions

Question 1

A company is deploying a new Amazon RDS for Oracle database in a VPC. The database must be accessed by an application running on an EC2 instance in a different subnet. Which THREE steps are required to allow this access?

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

Accepted Answer

Configure the network ACL for the RDS subnet to allow inbound traffic from the EC2 subnet.. The security group of the RDS instance must allow inbound traffic from the EC2 security group, which is option E. The VPC must have the 'Enable DNS hostnames' attribute set to true (option D) so that the RDS endpoint resolves correctly. Additionally, the network ACL for the RDS subnet must allow inbound traffic from the EC2 subnet (option C). Option A (VPC peering) is not needed because both resources are in the same VPC. Option B (Internet Gateway) is not needed because traffic is within the VPC and does not require internet access.

Answer

Create a VPC peering connection between the subnets.

Answer

Attach an Internet Gateway to the VPC.

Question 2

A company is migrating a 2 TB MongoDB database to Amazon DocumentDB. Which TWO factors should be considered when planning the migration?

Accepted Answer

Source MongoDB version compatibility with DocumentDB.. Amazon DocumentDB is wire-protocol-compatible with MongoDB 3.6 and 4.0, but not with all MongoDB versions. If the source MongoDB version is older or newer than these supported versions, you may need to upgrade or downgrade the source before migration. Compatibility also affects features like indexes, aggregation pipelines, and data types, which can cause migration failures if not addressed.

Option E is correct because network bandwidth and latency directly impact the time required to transfer a 2 TB dataset. Insufficient bandwidth can lead to prolonged migration windows or failures. Additionally, high latency can degrade performance of replication-based tools. Therefore, assessing network capacity and optimizing the transfer path is a critical planning factor.

Answer

DocumentDB stores backups in Amazon S3 automatically.

Answer

DocumentDB requires LDAP for authentication.

Answer

DocumentDB does not support encryption in transit.

Question 3

Refer to the exhibit. A company's production RDS MySQL instance 'mydb' is configured as shown. The application experiences write latency spikes during peak hours. Which action would most effectively reduce write latency?

Accepted Answer

Change the storage type to Provisioned IOPS (io1) and allocate sufficient IOPS.. The RDS MySQL instance uses gp2 storage with 500 GB, providing a baseline of 1500 IOPS (3 IOPS per GB). Write latency spikes during peak hours indicate that the workload is exceeding these IOPS, causing throttling. Changing to Provisioned IOPS (io1) allows allocating a higher, consistent IOPS level that matches the write workload, directly reducing write latency. Option D (Multi-AZ) adds synchronous replication overhead, increasing write latency. Option B (Read Replica) offloads reads, not writes. Option C (increasing storage) raises baseline IOPS but is less efficient and more costly than provisioning exact IOPS with io1.

Answer

Create a Read Replica in a different region.

Answer

Increase the allocated storage to 1 TB to improve baseline IOPS.

Answer

Enable Multi-AZ deployment to provide a standby instance.

Question 4

Refer to the exhibit. An IAM policy is attached to an IAM user that performs database migrations. When the user tries to start an AWS DMS replication task that writes to the RDS instance 'targetdb', the task fails with an access denied error. Which additional permission is required?

Accepted Answer

dms:DescribeReplicationInstances. The DMS replication task requires permission to describe the replication instance that is being used to run the task. The `dms:DescribeReplicationInstances` action allows the IAM user to retrieve metadata about the replication instance, which DMS needs to validate the instance state and configuration before starting the task. Without this permission, the start task operation fails with an access denied error even if the user has permissions to start the task itself.

Answer

dms:CreateEndpoint

Answer

dms:CreateReplicationInstance

Answer

rds:ModifyDBInstance on the source database

Question 5

Refer to the exhibit. A database specialist is taking a final snapshot of an RDS DB instance before deletion. The command returns the output shown. The snapshot is at 75% progress. What should the specialist do next?

Accepted Answer

Wait for the snapshot status to become 'available' before deleting the instance.. An RDS DB instance cannot be deleted while a final snapshot is in progress; the snapshot must reach the 'available' status first. The AWS CLI output shows the snapshot at 75% progress, meaning the snapshot is still being created. Attempting to delete the instance before the snapshot completes will result in an error, as the deletion operation requires the snapshot to be fully available.

Answer

Use the describe-db-snapshots command with --db-snapshot-identifier to get more details.

Answer

Use the stop-db-instance command to pause the snapshot.

Answer

Delete the DB instance immediately; the snapshot will continue in the background.

Question 6

A company is migrating a 5 TB Oracle database to Amazon Aurora PostgreSQL. The database has a 4-hour maintenance window weekly. Which migration approach minimizes downtime?

Accepted Answer

Use AWS Database Migration Service (DMS) with change data capture (CDC).. AWS DMS with CDC allows you to perform an initial full load of the 5 TB database and then continuously replicate ongoing changes from the source Oracle database to the target Aurora PostgreSQL. This minimizes downtime because you can keep the source database fully operational during the migration and only perform a brief cutover to switch applications to the new database, well within the 4-hour maintenance window.

Answer

Use Oracle Data Pump to export and pg_restore to import.

Answer

Use AWS Schema Conversion Tool (SCT) to convert schema and then copy data.

Answer

Use AWS DMS full load only and then manually sync.

Question 7

A company wants to migrate a 200 GB SQL Server database to Amazon RDS for SQL Server with minimal downtime. The database is used by a critical application. Which service should be used for the migration?

Accepted Answer

AWS Database Migration Service (DMS).. AWS DMS is the correct choice because it supports ongoing replication (change data capture) from a SQL Server source to an Amazon RDS for SQL Server target, enabling a migration with minimal downtime. DMS can perform a full load of the 200 GB database and then continuously replicate changes until the cutover, which is essential for a critical application that cannot tolerate extended downtime.

Answer

AWS Schema Conversion Tool (SCT).

Answer

SQL Server Import and Export Wizard.

Answer

SQL Server Management Studio (SSMS) backup and restore.

Question 8

A company is deploying a new application with a PostgreSQL database on Amazon RDS. The database must be highly available across two Availability Zones. Which deployment option meets this requirement?

Accepted Answer

Multi-AZ RDS instance.. A Multi-AZ RDS instance automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover for high availability. This ensures the database remains accessible even if the primary AZ fails, meeting the requirement for cross-AZ high availability.

Answer

RDS with a read replica in another AZ.

Answer

Single-AZ RDS instance.

Answer

Amazon Aurora Global Database.

Question 9

A company is migrating a 10 TB Oracle Data Warehouse to Amazon Redshift. The source database runs on premises with limited bandwidth (100 Mbps). The migration must complete within 5 days. Which approach is most cost-effective and meets the timeline?

Accepted Answer

Use AWS Snowball Edge to transfer the initial full load, then AWS DMS for ongoing changes.. The 10 TB dataset over a 100 Mbps link would take approximately 10 days (10 TB * 8 / 100 Mbps / 86400 seconds/day) for a full load, exceeding the 5-day window. AWS Snowball Edge provides a physical, high-bandwidth transfer for the initial full load, bypassing network constraints, and AWS DMS then captures and applies ongoing changes (CDC) to keep the target in sync. This combination is the most cost-effective as it avoids expensive Direct Connect and meets the timeline.

Answer

Use AWS DMS over the internet to migrate data.

Answer

Use AWS Schema Conversion Tool (SCT) to convert and then upload to S3.

Answer

Use AWS DMS with AWS Direct Connect at 1 Gbps.

Question 10

A company is deploying a MySQL database on Amazon RDS and needs to enforce encryption at rest. Which configuration step is required?

Accepted Answer

Select encryption option when creating the RDS instance.. Amazon RDS for MySQL requires encryption at rest to be enabled at instance creation time by selecting the encryption option in the AWS Management Console, CLI, or API. Encryption at rest uses AWS Key Management Service (KMS) to encrypt the underlying storage, automated backups, read replicas, and snapshots. This setting cannot be applied to an existing unencrypted DB instance, so it must be chosen during the initial launch.

Answer

Use a custom DB parameter group with SSL enabled.

Answer

Modify the DB instance to enable encryption after creation.

Answer

Enable SSL/TLS on the RDS instance.

Question 11

A company needs to migrate an on-premises PostgreSQL database to Amazon Aurora PostgreSQL with minimal downtime. Which AWS service should be used for the ongoing replication?

Accepted Answer

AWS Database Migration Service (DMS).. AWS Database Migration Service (DMS) supports ongoing replication (change data capture, CDC) from an on-premises PostgreSQL source to an Amazon Aurora PostgreSQL target using logical replication slots. This allows you to keep the target database synchronized with minimal downtime after the initial full load, making it the correct choice for a migration with minimal downtime.

Answer

AWS Glue.

Answer

AWS Backup.

Answer

AWS Schema Conversion Tool (SCT).

Question 12

A company is deploying a new web application that requires a highly available MariaDB database. The application is read-heavy and needs to scale read traffic. Which deployment approach meets these requirements?

Accepted Answer

Deploy a Multi-AZ RDS for MariaDB with one or more read replicas.. Deploying a Multi-AZ RDS for MariaDB provides high availability through automatic failover to a standby in a different Availability Zone, while adding one or more read replicas offloads read traffic from the primary instance, meeting the read-heavy scaling requirement. This combination ensures both fault tolerance and read scalability for a MariaDB database.

Answer

Deploy Amazon Aurora MySQL with a read replica.

Answer

Deploy a Multi-AZ RDS for MariaDB instance.

Answer

Deploy a single-AZ RDS for MariaDB with a read replica.

Question 13

A company is migrating a self-managed PostgreSQL database with extensions (PostGIS, pg_stat_statements) to Amazon RDS for PostgreSQL. After migration, they find that the extensions are not available. What is the most likely cause?

Accepted Answer

The required extensions are not included in the default parameter group and must be manually added to shared_preload_libraries.. Amazon RDS for PostgreSQL does not automatically load extensions that require shared library preloading, such as pg_stat_statements. These extensions must be explicitly added to the `shared_preload_libraries` parameter in the DB parameter group. PostGIS, while not requiring preloading, must be created via `CREATE EXTENSION` after the extension files are present; however, the most likely cause of extensions not being available is that the custom parameter group was not configured to include the required libraries in `shared_preload_libraries`.

Answer

The extensions are incompatible with the RDS engine version.

Answer

The RDS instance is not configured to allow extensions.

Answer

RDS does not support any PostgreSQL extensions.

Question 14

A company is migrating a 1 TB on-premises SQL Server database to Amazon RDS for SQL Server. The migration must be completed within 24 hours and with minimal downtime. Which TWO approaches should be used? (Choose 2)

Accepted Answer

Use AWS DMS with ongoing replication (CDC).. AWS DMS with ongoing replication (CDC) allows you to perform a full load of the existing data and then continuously replicate changes from the source SQL Server database to Amazon RDS for SQL Server, minimizing downtime to just the final cutover window. This approach meets the 24-hour migration window and the requirement for minimal downtime by keeping the target database nearly synchronized with the source until you are ready to switch.

Answer

Use AWS DMS with SSIS packages.

Answer

Use native backup and restore to S3.

Answer

Use AWS DMS full load only.

Question 15

A company is migrating a 5 TB Oracle database to Amazon Aurora PostgreSQL. They have a 4-hour maintenance window weekly. Which THREE steps should be taken to minimize downtime? (Choose 3)

Accepted Answer

Use AWS Snowball to transfer the initial data load.. AWS Snowball provides a physical data transfer mechanism that avoids saturating the network for the initial 5 TB load, which could otherwise take days over typical internet connections. This allows the bulk data to be loaded into Amazon S3 and then into Aurora PostgreSQL before the cutover, while AWS DMS with CDC (Option D) captures ongoing changes to keep the target synchronized with the source during the migration window. Option E is correct because the AWS Schema Conversion Tool (SCT) is essential for converting the Oracle schema (including data types, stored procedures, and indexes) to Aurora PostgreSQL-compatible format before data migration begins, ensuring compatibility and reducing downtime during the final sync.

Answer

Create an Aurora read replica for testing.

Answer

Use AWS Direct Connect for network connectivity.