DBS-C01 Deployment and Migration Practice Test 14 — 15 Questions

Question 1

A company wants to migrate an on-premises MongoDB database to Amazon DocumentDB. The migration must be performed with minimal downtime and should support live data synchronization. Which AWS service should be used?

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

Accepted Answer

AWS Database Migration Service (DMS) with ongoing replication.. AWS Database Migration Service (DMS) with ongoing replication is the correct choice because it supports continuous change data capture (CDC) from a source MongoDB database to Amazon DocumentDB, enabling live data synchronization with minimal downtime. DMS can perform a full load followed by ongoing replication using the MongoDB oplog to capture and apply changes in near real-time, which meets the requirement for minimal downtime during migration.

Answer

AWS Glue with streaming ETL jobs.

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AWS Data Pipeline to schedule periodic data loads.

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AWS S3 with AWS Lambda functions to sync data.

Question 2

A company is using an Amazon RDS for SQL Server database with Multi-AZ deployment. They need to migrate to Amazon RDS for SQL Server in a different AWS region. The database is 1 TB and cannot tolerate more than 15 minutes of downtime. Which strategy minimizes downtime?

Accepted Answer

Set up cross-region replication using native SQL Server log shipping or DMS with ongoing replication, then perform a DNS cutover to the target instance.. It combines native SQL Server log shipping or AWS DMS with ongoing replication to keep the target region instance nearly synchronized with the source, enabling a DNS cutover with minimal downtime. This approach meets the 15-minute downtime requirement by allowing a controlled final sync and cutover, unlike snapshot restore or full-load-only methods that require longer outages. Multi-AZ deployment does not prevent cross-region replication, and log shipping or DMS can handle the 1 TB database within the downtime window if properly configured.

Answer

Create a cross-region read replica in the target region and promote it to a standalone instance.

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Take a snapshot of the source RDS instance and restore it in the target region. Then update the application connection string.

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Use AWS DMS to perform a full load to a new RDS instance in the target region. During the final sync, stop the source and resume from the target.

Question 3

A company is migrating a 50 GB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL. The network bandwidth between on-premises and AWS is 50 Mbps. The migration must complete within 24 hours. What is the most efficient way to transfer the initial data?

Accepted Answer

Use pg_dump to export the database and upload to S3 via the internet, then restore into RDS.. The most efficient method is to use pg_dump to export the database, upload the dump file to Amazon S3 via the internet (or using AWS CLI with multipart upload), and then restore it into Amazon RDS for PostgreSQL. Given the database size of 50 GB and a 50 Mbps link, the theoretical transfer time is about 2.3 hours, and even with realistic overhead and retransmissions, it can complete well within the 24-hour window. This approach avoids the shipping delay and logistical overhead of AWS Snowball, which would take several days to arrive and process.

Answer

Use AWS Snowball to physically transfer the database backup to AWS, then load into RDS.

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Use AWS DMS to perform a full load directly over the internet.

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Set up a VPN connection and use AWS DMS with ongoing replication.

Question 4

A company is migrating a 10 GB MySQL database to Amazon RDS for MySQL. They have a 1 Gbps connection to AWS. The migration must be completed in the least amount of time with minimal manual effort. Which tool should be used?

Accepted Answer

AWS Database Migration Service (DMS).. AWS Database Migration Service (DMS) is the correct choice because it can perform a live, continuous migration of a 10 GB MySQL database to Amazon RDS for MySQL with minimal downtime and manual effort. DMS handles schema conversion (if needed), data replication, and ongoing changes via Change Data Capture (CDC), allowing the migration to complete in the least amount of time while automatically managing the full load and sync process over the 1 Gbps connection.

Answer

AWS Schema Conversion Tool (SCT).

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AWS Snowball Edge.

Answer

mysqldump and mysql command-line tools.

Question 5

A company is migrating an on-premises Oracle database to Amazon Aurora PostgreSQL. They used AWS SCT to convert the schema, but some stored procedures failed to convert automatically. What is the best course of action?

Accepted Answer

Manually rewrite the unconverted stored procedures to PostgreSQL-compatible code based on SCT's assessment report.. AWS SCT provides an assessment report that identifies unconverted stored procedures and suggests manual rewrites. Since Oracle and PostgreSQL have fundamentally different procedural languages (PL/SQL vs. PL/pgSQL), automated conversion cannot handle all syntax and semantic differences. Manually rewriting the unconverted procedures based on SCT's report ensures compatibility and correctness, as SCT highlights the specific lines and constructs that need attention.

Answer

Use AWS Lambda to automatically convert the stored procedures.

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Use AWS DMS to replicate the Oracle stored procedures as-is to Aurora.

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Switch to Amazon RDS for Oracle to avoid conversion issues.

Question 6

A company is planning to migrate a 5 TB Oracle data warehouse to Amazon Redshift. The migration must be completed within a 2-day maintenance window. The source database is heavily normalized and uses complex joins. Which strategy is most appropriate?

Accepted Answer

Use AWS SCT to convert the Oracle schema to Redshift-compatible format, then use AWS DMS to load the data.. AWS Schema Conversion Tool (SCT) is specifically designed to convert Oracle schemas (including heavily normalized structures with complex joins) into Amazon Redshift-compatible format, which is essential for a data warehouse migration. AWS DMS then efficiently loads the converted schema and data into Redshift within the 2-day window, as it can handle large volumes with full load and ongoing replication if needed.

Answer

Use AWS DMS to directly migrate data to Redshift with full load and ongoing replication.

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Export data to flat files, use S3 Transfer Acceleration to upload to S3, then COPY into Redshift.

Answer

Use AWS Glue to crawl the Oracle schema and create Redshift tables, then run a Glue ETL job to load data.

Question 7

A company wants to test an application against an Amazon RDS for MySQL database with a recent set of production data without impacting the production database. The test database must be available quickly and be refreshed regularly. Which solution should be used?

Accepted Answer

Create a read replica of the production database, then promote it to a standalone instance for testing.. Creating a read replica of the production RDS for MySQL database and then promoting it to a standalone instance is the fastest way to obtain a near-current copy of production data without impacting the source. The replica is created asynchronously using MySQL's native binlog replication, and promotion breaks the replication link, leaving a fully writable test instance. This approach minimizes setup time because the replica is already hydrated with data from the moment of creation.

Answer

Export production data to S3 and import into a test instance using Lambda.

Answer

Use AWS DMS to continuously replicate data from production to a test RDS instance.

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Create a snapshot of the production database and restore it as a new RDS instance.

Question 8

A company is migrating a 200 GB Oracle database to Amazon Aurora MySQL. They want to minimize downtime and ensure data consistency. Which two services should they use together? (Choose TWO.)

Accepted Answer

AWS Schema Conversion Tool (SCT). AWS Schema Conversion Tool (SCT) is required to convert the Oracle database schema (including stored procedures, functions, and data types) to a format compatible with Amazon Aurora MySQL. AWS Database Migration Service (DMS) then performs the continuous data replication from Oracle to Aurora MySQL, enabling near-zero downtime migration while maintaining data consistency through Change Data Capture (CDC).

Answer

AWS Snowball Edge

Answer

AWS Data Pipeline

Answer

Amazon EC2 with Oracle installed

Question 9

A company is migrating a 500 GB PostgreSQL database from on-premises to Amazon Aurora PostgreSQL. They need to minimize downtime and ensure that all data changes made during migration are synchronized. Which three components are required for this migration? (Choose THREE.)

Accepted Answer

AWS Database Migration Service (DMS) replication instance. AWS DMS replication instance is required because it orchestrates the continuous replication of data from the source PostgreSQL database to the target Aurora PostgreSQL cluster. It manages the connection, reads changes from the source using logical replication slots, and applies them to the target, enabling near-zero downtime migration.

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS VPN connection between on-premises and AWS

Question 10

A database administrator runs the command shown in the exhibit to create a read replica in us-west-2 from a source DB instance in us-east-1. The command fails. What is the most likely cause?

Accepted Answer

The source DB instance does not have backup retention enabled.. The command fails because creating a cross-Region read replica requires the source DB instance to have automated backups enabled (backup retention period > 0). Without backups, Amazon RDS cannot generate the necessary transaction logs to replicate data to the replica in us-west-2. This is a prerequisite for any read replica creation, whether in the same Region or across Regions.

Answer

The source DB instance is not publicly accessible.

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The replica instance class db.r5.large is not available in us-west-2.

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The replica must use the same DB instance class as the source.

Question 11

A user has the IAM policy shown in the exhibit. When attempting to create a DMS replication task, they receive an authorization error. What is the most likely missing permission?

Accepted Answer

dms:CreateEndpoint permission. The user is attempting to create a DMS replication task, which requires the ability to create the underlying DMS resources. The error indicates a missing permission for the `dms:CreateEndpoint` action, as DMS replication tasks depend on source and target endpoints that must be created first. Without this permission, the API call to create the endpoint fails, resulting in an authorization error.

Answer

ec2:DescribeSecurityGroups to allow network configuration

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s3:PutObject for the S3 bucket

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logs:CreateLogGroup to enable logging

Question 12

After migrating a database to Amazon RDS, an application on an EC2 instance in the same VPC cannot connect. The command in the exhibit shows the endpoint. What is the most likely cause?

Accepted Answer

The security group for the DB instance does not allow inbound traffic from the EC2 instance's security group.. The most likely cause is that the security group for the RDS DB instance does not have an inbound rule allowing traffic from the EC2 instance's security group on the database port (typically TCP 3306 for MySQL or 5432 for PostgreSQL). Even though both resources are in the same VPC, security groups act as virtual firewalls that must explicitly permit inbound connections from the source. The command output showing the endpoint confirms the DNS resolution works, so the issue is at the network access control layer.

Answer

The EC2 instance is in a different VPC and needs a VPN connection.

Answer

The DB instance endpoint is incorrect.

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The DB instance is not publicly accessible.

Question 13

A company is migrating a 2 TB Oracle database to Amazon Aurora PostgreSQL. They need to minimize downtime. Which AWS service should they use?

Accepted Answer

AWS Database Migration Service (DMS). AWS DMS can perform a live migration from Oracle to Aurora PostgreSQL with minimal downtime by continuously replicating ongoing changes from the source database to the target using Change Data Capture (CDC). For a 2 TB database, DMS supports full-load plus CDC, allowing the source to remain operational during the initial load and then switching over with only a brief outage to apply final changes.

Answer

AWS Schema Conversion Tool (SCT)

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AWS Data Pipeline

Answer

AWS Snowball

Question 14

A company is deploying a new application that uses Amazon RDS for MySQL. The database must be highly available with automatic failover. Which deployment configuration meets these requirements?

Accepted Answer

Multi-AZ deployment with a standby replica in a different Availability Zone. A Multi-AZ deployment for Amazon RDS for MySQL 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 within a single AWS region.

Answer

Single-AZ with a Read Replica in the same region

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Multi-AZ deployment with synchronous replication to a cross-region replica

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Single-AZ with automated backups

Question 15

A developer needs to migrate a 500 GB MongoDB database to Amazon DocumentDB. Which approach will minimize application downtime?

Accepted Answer

Use AWS DMS with ongoing replication from MongoDB to DocumentDB. AWS DMS with ongoing replication (change data capture) allows you to perform a full load of the existing 500 GB MongoDB data into DocumentDB while continuously replicating new changes from the source. This minimizes application downtime because you can cut over to DocumentDB only after the target is fully synchronized, rather than taking the source offline for the entire migration duration.

Answer

Write a custom script to migrate data in batches

Answer

Export data from MongoDB, upload to S3, and import into DocumentDB

Answer

Use AWS DataSync to transfer data files