DBS-C01 Deployment and Migration Practice Test 9 — 15 Questions

Question 1

Which THREE actions should be taken to prepare for a migration of an on-premises MySQL database to Amazon RDS for MySQL with minimal downtime using AWS DMS?

Accepted Answer

Enable binary logging on the source MySQL database. AWS DMS requires binary logging (binlog) to be enabled on the source MySQL database for ongoing replication (change data capture). DMS reads the binary log to capture inserts, updates, and deletes in near real-time, which is essential for minimizing downtime during migration.

Answer

Disable foreign key checks on the source database

Answer

Take a full backup of the source database

Question 2

Which TWO AWS services can be used to migrate an on-premises SQL Server database to Amazon RDS for SQL Server?

Accepted Answer

AWS DMS. AWS DMS (Database Migration Service) is correct because it is purpose-built for migrating databases to AWS with minimal downtime, supporting homogeneous migrations like SQL Server to Amazon RDS for SQL Server. It uses change data capture (CDC) to replicate ongoing changes, enabling near-zero downtime migrations. Native SQL Server backup to S3 and restore to RDS is also correct because SQL Server's native backup/restore mechanism can be used to take a full backup, upload it to Amazon S3, and then restore it directly onto an RDS for SQL Server instance, which is a supported and common offline migration method.

Answer

AWS DataSync

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AWS Storage Gateway

Answer

AWS DynamoDB

Question 3

Refer to the exhibit. A company is migrating from an on-premises MySQL database to Amazon RDS for MySQL. The DBA wants to connect to the RDS instance using the endpoint shown. What additional step is required to allow the DBA's client to connect?

Accepted Answer

Modify the security group to allow inbound traffic on port 3306 from the client IP. Amazon RDS security groups act as a virtual firewall controlling inbound and outbound traffic. By default, no inbound traffic is allowed on port 3306 (MySQL). To permit the DBA's client to connect, you must modify the security group associated with the RDS instance to add an inbound rule that allows TCP traffic on port 3306 from the client's IP address (or a range that includes it). Without this rule, the connection is blocked at the network level regardless of other configurations.

Answer

Create a Route 53 record for the endpoint

Answer

Create a MySQL user that matches the client's IP

Answer

Change the RDS instance to be publicly accessible

Question 4

Refer to the exhibit. An IAM policy is attached to a user who will manage AWS DMS tasks. When the user tries to start a replication task, they receive an access denied error. What is the most likely cause?

Accepted Answer

The policy is missing permissions to describe endpoints and connections. The DMS API requires that a user have permissions to describe endpoints and connections before starting a replication task. Even if the policy grants dms:StartReplicationTask, the service internally calls dms:DescribeEndpoints and dms:DescribeConnections to validate the source and target endpoints. Without those describe permissions, the API call fails with an access denied error, even though the start action itself is allowed.

Answer

The policy does not allow rds:DescribeDBInstances

Answer

The policy does not allow the dms:StartReplicationTask action

Answer

The policy does not allow dms:CreateReplicationTask

Question 5

Refer to the exhibit. A DBA is monitoring a DMS migration task from on-premises Oracle to Amazon RDS for Oracle. The full load completed successfully with 50 tables. However, the DBA notices that the CDC phase has not started. What is the most likely reason?

Accepted Answer

The replication task was stopped after the full load completed. The most likely reason the CDC phase has not started is that the replication task was stopped after the full load completed. In AWS DMS, after the full load finishes, the task must remain in a running state to transition to the CDC phase. If the task is stopped, CDC cannot begin, and the DBA would need to resume or restart the task to capture ongoing changes.

Answer

The task was not configured with CDC enabled

Answer

The full load encountered errors on some tables

Answer

The source Oracle database is not generating redo logs

Question 6

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 5 TB in size and has a daily change rate of 2%. The migration must have minimal downtime. Which migration strategy should be used?

Accepted Answer

Use AWS Database Migration Service (DMS) with ongoing replication from the source database.. AWS DMS with ongoing replication (change data capture, CDC) allows a full load of the 5 TB database followed by continuous replication of the 2% daily changes, minimizing downtime by keeping the target RDS instance nearly synchronized until cutover. This approach handles large databases and high change rates without requiring a lengthy final export/import window.

Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema, then use AWS DMS for full load only.

Answer

Create an RDS read replica in the same region and promote it.

Answer

Export the database to a dump file using Oracle Data Pump, upload to S3, and restore to RDS.

Question 7

A company wants to migrate a 2 TB Amazon RDS for MySQL DB instance to Amazon Aurora MySQL. The migration must have zero downtime and must be reversible for 48 hours. Which strategy meets these requirements?

Accepted Answer

Create an Aurora MySQL Read Replica from the RDS MySQL instance, then promote the replica to a standalone Aurora cluster.. Creating an Aurora MySQL Read Replica from an RDS MySQL instance uses MySQL's native asynchronous replication to keep the Aurora cluster in sync with the source, allowing a near-zero-downtime cutover by promoting the replica. The migration is fully reversible within 48 hours because the original RDS instance remains unchanged and can continue serving traffic if the promotion is rolled back.

Answer

Take a snapshot of the RDS MySQL instance, restore it to Aurora MySQL, and update the DNS.

Answer

Export the database using mysqldump, import into Aurora, and switch DNS.

Answer

Use AWS DMS with ongoing change data capture (CDC) to migrate to Aurora.

Question 8

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

Accepted Answer

Deploy RDS PostgreSQL with Multi-AZ configuration.. Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone. If the primary DB instance fails, Amazon RDS automatically fails over to the standby, providing high availability with automatic failover across two AZs. This meets the requirement without manual intervention or application changes.

Answer

Deploy RDS PostgreSQL in a cross-region replication setup.

Answer

Deploy RDS PostgreSQL in a single Availability Zone.

Answer

Deploy RDS PostgreSQL with a read replica in another AZ.

Question 9

A company is migrating a 500 GB MongoDB database to Amazon DocumentDB. The migration must have minimal impact on the source database. Which approach should the company take?

Accepted Answer

Use AWS Database Migration Service (DMS) with MongoDB as source and DocumentDB as target.. AWS DMS supports ongoing replication from MongoDB to Amazon DocumentDB, enabling a live migration with minimal impact on the source database. DMS uses the MongoDB oplog to capture changes continuously, so the source is only read during the initial load and then tailed for CDC, avoiding heavy locks or performance degradation.

Answer

Use mongodump to export the data, then use mongorestore to import into DocumentDB.

Answer

Use mongoexport to export CSV, then use the DocumentDB import tool.

Answer

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

Question 10

A company needs to migrate a 3 TB Amazon RDS for SQL Server database to Amazon RDS for PostgreSQL. The migration must be automated and repeatable with minimal manual intervention. Which combination of services should be used?

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the schema, then use AWS DMS to migrate the data.. AWS Schema Conversion Tool (SCT) handles the schema conversion from SQL Server to PostgreSQL, which is necessary due to incompatible data types, stored procedures, and indexes. AWS Database Migration Service (DMS) then performs the continuous data migration with minimal downtime, supporting both full load and ongoing replication. This combination automates the migration process and makes it repeatable via AWS CloudFormation or DMS task templates.

Answer

Use AWS SCT to convert the schema and export data to PostgreSQL-compatible format, then import.

Answer

Use AWS DMS with native SQL Server CDC to migrate directly to PostgreSQL.

Answer

Use Microsoft Data Migration Assistant to assess and migrate to PostgreSQL.

Question 11

A company is deploying a new application that requires a MySQL-compatible database with automatic scaling of compute and storage resources. Which AWS service should be used?

Accepted Answer

Amazon Aurora MySQL. Amazon Aurora MySQL is the correct choice because it is a MySQL-compatible relational database that automatically scales compute (up to 128 vCPUs and 244 GiB of memory) and storage (up to 128 TiB in 10 GiB increments) without downtime. Aurora's storage subsystem is distributed and self-healing, scaling as data grows, and its compute can be scaled via Auto Scaling policies or by modifying the instance class with minimal disruption.

Answer

Amazon RDS for MySQL

Answer

Amazon DynamoDB

Answer

Amazon Redshift

Question 12

A company is migrating a 1 TB Amazon RDS for Oracle database to Amazon RDS for PostgreSQL. The migration must be completed within a 4-hour maintenance window. The database has a high volume of transactions. Which migration method minimizes risk of data loss?

Accepted Answer

Use AWS DMS with a full load and change data capture (CDC) enabled, with task restart and validation.. AWS DMS with full load and CDC enables continuous replication of ongoing transactions after the initial load, minimizing data loss risk during the migration window. The task restart and validation features ensure resilience against transient failures and data integrity checks, critical for a high-volume transactional database. This approach meets the 4-hour window by allowing the full load to complete within the window while CDC captures any changes that occur during and after the load.

Answer

Use AWS SCT to convert the schema, then use AWS DMS for full load and ongoing replication.

Answer

Set up Oracle log shipping to an EC2 instance, then restore to RDS PostgreSQL.

Answer

Export the Oracle database using Data Pump, import to PostgreSQL using pgloader.

Question 13

A company wants to deploy a globally distributed application with a DynamoDB table that uses optimistic locking. Which DynamoDB feature should be used to implement this?

Accepted Answer

DynamoDB Conditional Writes. Optimistic locking in DynamoDB is implemented using conditional writes, specifically the `ConditionExpression` parameter in `PutItem`, `UpdateItem`, or `DeleteItem` operations. By checking that a version attribute (e.g., `version = :expected_version`) matches the client's known value before writing, the application can detect and reject concurrent modifications, ensuring data consistency without locking the entire table.

Answer

DynamoDB Streams

Answer

DynamoDB Global Tables

Answer

DynamoDB Transactions

Question 14

A company is migrating a 10 TB Amazon RDS for MySQL database to Amazon Aurora MySQL. The migration must have minimal downtime and must support point-in-time recovery for the source during migration. Which approach meets these requirements?

Accepted Answer

Create a read replica of the source RDS instance, use AWS DMS with CDC from the read replica to Aurora, then promote Aurora.. Creating a read replica of the source RDS for MySQL instance and using AWS DMS with Change Data Capture (CDC) from that replica allows the migration to proceed with minimal downtime. The read replica offloads the CDC overhead from the source, and CDC captures ongoing changes after the full load, enabling a near-zero-downtime cutover. Additionally, the source RDS instance remains fully available for point-in-time recovery (PITR) throughout the migration, as the read replica does not interfere with the source's backup or transaction log retention.

Answer

Use mysqldump to export the database, import into Aurora, and point DNS to Aurora.

Answer

Use AWS DMS with CDC directly from the source RDS instance to Aurora.

Answer

Take a snapshot of the source RDS instance, restore to Aurora, and point DNS to Aurora.

Question 15

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. Which TWO AWS services can be used to assess the source database for compatibility and migration readiness?

Accepted Answer

AWS Schema Conversion Tool (SCT). AWS Schema Conversion Tool (SCT) is designed to assess source databases for compatibility by analyzing the schema, code objects, and dependencies, then generating a detailed assessment report that identifies conversion complexity and migration readiness. For PostgreSQL to Amazon RDS for PostgreSQL migrations, SCT validates that the source schema is compatible with the target RDS engine version and highlights any deprecated features or required modifications.

Answer

Amazon Kinesis

Answer

AWS Glue

Answer

Amazon CloudWatch