DBS-C01 Deployment and Migration Practice Test 17 — 15 Questions

Question 1

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?

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

Accepted Answer

Use DynamoDB global tables. DynamoDB global tables provide a fully managed, multi-Region, multi-active solution that automatically replicates data across selected AWS Regions, delivering eventual consistency and high availability for applications accessed from multiple Regions. This is the most appropriate strategy because it natively supports the requirement without custom code or additional infrastructure.

Answer

Use DynamoDB auto scaling to handle regional traffic

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Use DynamoDB Accelerator (DAX) to cache data across regions

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Use DynamoDB Streams to replicate data to another region

Question 2

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. Native backup and restore to Amazon RDS for SQL Server is the fastest and most reliable method for migrating a large database like 5 TB with minimal downtime. By taking a full backup, uploading it to Amazon S3, and restoring it to RDS, you avoid the overhead of ongoing replication setup and can schedule the final cutover during a brief maintenance window. This approach leverages RDS's native support for restoring from S3, ensuring data integrity and minimizing the migration window.

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 3

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. Redis replication (using the REPLICAOF or SLAVEOF command) allows you to set up the ElastiCache cluster as a read-replica of the self-managed Redis cluster, enabling continuous, asynchronous replication with minimal downtime. Once the replica is fully synchronized, you can promote it to the primary role with a brief failover, achieving a near-zero-downtime migration. This approach is ideal for a 100 GB cluster with high write throughput, as it avoids the performance impact of snapshotting or dump/restore operations.

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

Question 4

A company is deploying a new application that uses Amazon RDS for PostgreSQL. The database must be highly available and fault-tolerant. Which deployment option meets these requirements?

Accepted Answer

Deploy the RDS instance with Multi-AZ configuration. Amazon RDS Multi-AZ deployment automatically provisions and maintains a synchronous standby replica in a different Availability Zone, providing automatic failover in the event of an AZ outage or primary instance failure. This configuration meets the requirements for high availability and fault tolerance by ensuring the database remains accessible with minimal downtime, as the standby replica is kept in sync synchronously and DNS is updated to point to the standby upon failover.

Answer

Deploy the RDS instance in a single Availability Zone

Answer

Deploy the RDS instance across multiple AWS Regions

Answer

Deploy the RDS instance with multiple read replicas

Question 5

A company is migrating a 500 GB MySQL database to Amazon Aurora MySQL. The migration must have minimal downtime and the source database is already using binary logging. Which migration approach should be used?

Accepted Answer

Set up binary log replication from the source to an Aurora MySQL cluster. MySQL native binary log replication can be set up directly from a source MySQL database to an Amazon Aurora MySQL cluster. Since binary logging is already enabled, the Aurora cluster can act as a replica, synchronizing continuously with minimal downtime. This approach allows a full load followed by ongoing replication, meeting the requirement for near-zero downtime migration.

Answer

Take a snapshot of the source database and restore to Aurora

Answer

Use AWS DMS with full load only

Answer

Use mysqldump to export the data and import into Aurora

Question 6

A company needs to migrate a 1 TB Oracle database to Amazon RDS for Oracle. The migration must have minimal downtime and the source database is running on-premises. Which TWO AWS services should be used together to achieve this?

Accepted Answer

AWS Database Migration Service (DMS). To migrate a 1 TB Oracle database to Amazon RDS for Oracle with minimal downtime, two services are required. AWS Database Migration Service (DMS) performs the initial full load and then uses Change Data Capture (CDC) to continuously replicate ongoing changes, minimizing downtime. AWS Direct Connect establishes a dedicated network connection between the on-premises environment and AWS, ensuring stable and high-bandwidth data transfer necessary for the large database migration. Without Direct Connect, the replication could be impacted by internet latency or outages.

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS CloudEndure Migration

Answer

AWS Direct Connect

Question 7

A company is deploying an Amazon DynamoDB table with on-demand capacity mode. The table will be accessed from multiple AWS Regions and requires strong consistency. Which THREE steps should be taken to meet these requirements?

Accepted Answer

Create a global secondary index. None of the options correctly meet the requirements. DynamoDB global tables provide multi-Region access but only eventual consistency, and strongly consistent reads are limited to the source Region. A global secondary index does not enable cross-Region access. Therefore, no combination of the listed steps can achieve strong consistency across multiple Regions.

Answer

Use DynamoDB Accelerator (DAX)

Answer

Configure auto scaling

Answer

Use strongly consistent reads

Question 8

A company is migrating an on-premises PostgreSQL database to Amazon RDS for PostgreSQL. The migration must be completed with minimal downtime. Which TWO AWS services should be used together?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication from an on-premises PostgreSQL source to Amazon RDS for PostgreSQL, enabling near-zero downtime migrations. DMS uses change data capture (CDC) to continuously replicate transactions after an initial full load, allowing the target database to stay synchronized until cutover.

Answer

AWS Snowball

Answer

AWS CloudEndure Migration

Answer

AWS Direct Connect

Question 9

Refer to the exhibit. A company is creating an IAM policy for a migration engineer who needs to perform a database migration from an on-premises SQL Server to Amazon RDS for SQL Server using AWS DMS. The policy is attached to the engineer's IAM user. Which additional permission is required for the engineer to create a DMS replication instance?

Accepted Answer

ec2:CreateInstance (or equivalent). To create a DMS replication instance, AWS DMS launches an Amazon EC2 instance in the customer's VPC to run the replication engine. The IAM user must have permission to call ec2:RunInstances (or the equivalent ec2:CreateInstance action) to provision this underlying compute resource. Without this EC2 permission, the DMS service cannot spin up the replication instance, and the migration engineer will receive an authorization error.

Answer

kms:CreateKey

Answer

dms:CreateEndpoint

Answer

s3:PutObject

Question 10

Refer to the exhibit. A company is creating an Aurora MySQL cluster using the AWS CLI. The command fails with an error. The company has a default KMS key but the command specifies a customer-managed KMS key. What is the most likely cause of the failure?

Accepted Answer

The IAM user does not have permission to use the specified KMS key. The most likely cause of the failure is that the IAM user does not have the required permissions to use the specified customer-managed KMS key. When you specify a KMS key in the `--kms-key-id` parameter for an Aurora MySQL cluster, the IAM user must have `kms:CreateGrant`, `kms:Decrypt`, and `kms:Encrypt` permissions on that key. If the user lacks these permissions, the command fails even if the key exists and is in the correct region.

Answer

The --kms-key-id parameter is not supported for aurora-mysql engine

Answer

The KMS key does not exist

Answer

The KMS key is in a different region

Question 11

Refer to the exhibit. A company is migrating an on-premises database to Amazon RDS for MySQL. During a test migration, the DMS task fails with the error shown. The source database is 500 GB and the target RDS instance has 500 GB allocated storage. What should be done to resolve this error and complete the migration?

Accepted Answer

Enable storage autoscaling on the RDS instance. The error indicates that the target RDS instance ran out of storage during the migration. Enabling storage autoscaling allows RDS to automatically increase storage when free space is low, preventing the migration from failing due to insufficient disk space. This is the correct resolution because the source database is 500 GB and the target has exactly 500 GB allocated, leaving no room for temporary data or logs during the migration.

Answer

Increase the DB instance class to a larger size

Answer

Increase the DMS task's allocated storage

Answer

Reduce the size of the source database

Question 12

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database is 500 GB in size and has a 24-hour maintenance window. Which AWS service or tool should be used for the initial data transfer with minimal downtime?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication from a source MySQL database to Amazon RDS for MySQL, allowing you to perform a full load followed by continuous change data capture (CDC) to minimize downtime. With a 500 GB database and a 24-hour maintenance window, DMS can complete the initial load and then keep the target in sync until you cut over, achieving near-zero downtime.

Answer

Amazon S3 with AWS Glue

Answer

AWS Snowball Edge

Answer

mysqldump and restore to RDS

Question 13

A company is migrating a 2 TB Oracle database from on-premises to Amazon RDS for Oracle using AWS DMS. The migration completes successfully, but the new RDS instance shows higher CPU utilization than the on-premises database for the same workload. Which action is MOST likely to reduce CPU utilization on RDS?

Accepted Answer

Increase the allocated storage to improve IOPS. Increasing allocated storage on Amazon RDS for Oracle directly improves the provisioned IOPS (if using Provisioned IOPS) or baseline IOPS (for gp2/gp3). Higher IOPS reduces I/O wait time, which is a common cause of high CPU utilization when the database is I/O-bound. Query optimization or instance resizing may also help, but increasing storage is a simple, low-risk action that often alleviates I/O-related CPU pressure. Option B is incorrect because Oracle Multitenant (CDB/PDB) architecture adds container management overhead and is not designed to reduce CPU utilization; also, converting an existing non-CDB RDS instance to CDB is not supported.

Answer

Disable automated backups to free resources

Answer

Enable Oracle Multitenant architecture

Answer

Change the RDS instance to a burstable class

Question 14

A financial services company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. The source database uses a combination of partitioned tables, indexes, and materialized views. The migration team plans to use AWS SCT and DMS. Which approach should the team take to optimize query performance after migration?

Accepted Answer

Define appropriate distribution keys and sort keys. Amazon Redshift is a columnar data warehouse that does not support traditional indexes or the PARTITION BY clause used in Oracle. Instead, query performance in Redshift is optimized by defining appropriate distribution keys (to minimize data shuffling across nodes) and sort keys (to enable zone maps and reduce the amount of data scanned). This approach directly addresses the performance needs of the migrated 10 TB data warehouse.

Answer

Create indexes on frequently queried columns

Answer

Recreate all materialized views using standard views

Answer

Partition tables by date using the PARTITION BY clause

Question 15

A company is migrating a PostgreSQL database to Amazon Aurora PostgreSQL. To minimize downtime, they plan to use the AWS DMS with change data capture (CDC). During the full load phase, DMS reports an error: 'Failed to add foreign key constraint'. What is the most likely cause?

Accepted Answer

Referential integrity violations in the source data. The error 'Failed to add foreign key constraint' during the full load phase of AWS DMS indicates that the source data contains referential integrity violations. DMS attempts to apply foreign key constraints on the target Aurora PostgreSQL after loading data, but if parent-child relationships are broken (e.g., orphan rows), the constraint creation fails. This is a common issue when migrating databases with existing data integrity problems, as DMS does not automatically validate or fix source data.

Answer

CDC is incompatible with foreign key constraints

Answer

The target table lacks a primary key

Answer

Data type mismatch between source and target