DBS-C01 Deployment and Migration Practice Test 7 — 15 Questions

Question 1

A company is deploying a new Amazon RDS for MariaDB instance. The database must be accessible from a specific set of EC2 instances in a VPC. How should the company configure security to allow access?

Accepted Answer

Create a security group for the RDS instance that allows inbound traffic from the EC2 instances' security group.. The recommended way to allow access from EC2 instances to an RDS instance is to create a security group for the RDS instance that allows inbound traffic on the database port from the security group attached to the EC2 instances. This leverages security group referencing, which is more secure and easier to manage than specifying IP addresses.

Option A is incorrect because while assigning the same security group to both could work, it is not a best practice as it would allow all members of that group to communicate without granularity, and it does not follow the principle of least privilege.

Option C is incorrect because IAM roles are used for authentication and authorization to AWS services, not for network-level access control. To access the RDS database, you still need to allow network traffic via a security group or NACL.

Option D is incorrect because network ACLs are stateless and operate at the subnet level. While they can be used, security groups are the preferred method for controlling traffic to an RDS instance because they are stateful and more granular.

Answer

Assign the same security group to both the RDS instance and the EC2 instances.

Answer

Attach an IAM role to the EC2 instances that grants access to the RDS database.

Answer

Configure a network ACL to allow inbound traffic from the EC2 instance IPs.

Question 2

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

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS Database Migration Service (DMS) is used for the actual data migration with minimal downtime, supporting ongoing replication via change data capture (CDC) from the on-premises PostgreSQL database to Amazon RDS for PostgreSQL. AWS Schema Conversion Tool (SCT) is required to convert the source database schema and code to match the target RDS for PostgreSQL, identifying and resolving any compatibility issues. Together, SCT pre-processes the schema and DMS performs the data migration with replication, enabling a near-zero downtime migration.

Answer

AWS DataSync

Answer

AWS CloudEndure Migration

Answer

AWS Direct Connect

Question 3

A company is deploying a new Amazon RDS for Oracle instance and needs to ensure high availability and automatic failover. Which configuration should be used?

Accepted Answer

Multi-AZ deployment. (Multi-AZ deployment) is correct because it provisions a synchronous standby replica in a different Availability Zone, enabling automatic failover without data loss when the primary instance fails. This meets the high availability and automatic failover requirements for Amazon RDS for Oracle. Option D (Automated backups with point-in-time recovery) provides backup and recovery capabilities but does not ensure high availability or automatic failover; it is not a configuration for automatic failover.

Answer

Read Replicas in a different Region

Answer

Enhanced Monitoring

Answer

Automated backups with point-in-time recovery

Answer

Deletion protection

Question 4

A company is migrating a 2 TB Oracle database to Amazon Aurora PostgreSQL. The migration requires ongoing replication for minimal downtime. Which THREE AWS services should be used?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct choice because it supports ongoing replication (change data capture) from Oracle to Amazon Aurora PostgreSQL, enabling minimal downtime migration. It can continuously replicate changes from the source Oracle database to the target Aurora PostgreSQL instance until the cutover, allowing the source to remain operational during the migration.

Answer

AWS DataSync

Answer

AWS Lambda

Question 5

A database administrator is trying to delete the RDS instance named 'prod-critical' using the AWS CLI. The IAM policy shown is attached to the user. What will happen?

Accepted Answer

The delete will fail because the Deny statement explicitly denies the action for that resource.. The Deny statement in the policy explicitly denies the 'rds:DeleteDBInstance' action on the resource 'arn:aws:rds:*:*:db:prod-critical'. In AWS IAM, an explicit Deny always overrides any Allow, so the delete will fail. Option A is incorrect because a condition is not relevant; the Deny is unconditional. Option C is incorrect because the policy has no syntax error. Option D is incorrect because the Allow does not apply due to the overriding Deny.

Answer

The delete will succeed only if the user includes a condition.

Answer

The delete will fail because the policy has a syntax error.

Answer

The delete will succeed because the Allow statement grants permission.

Question 6

A developer is connecting to an RDS for MySQL instance. What is the endpoint address that should be used in the database connection string?

Accepted Answer

mydb.123456789012.us-east-1.rds.amazonaws.com. When connecting to an Amazon RDS for MySQL instance, the endpoint is a fully qualified domain name (FQDN) that resolves to the underlying database host. Option B provides the correct FQDN format: a DB instance identifier followed by a randomly generated alphanumeric string, the AWS region, and the rds.amazonaws.com domain. This endpoint is found in the RDS console under the instance's 'Connectivity & security' tab and is required by MySQL clients to establish a TCP connection.

Answer

mydb

Answer

3306

Answer

Z1R2S3V4X5Y6Z7

Question 7

A company wants to migrate an on-premises Oracle database to Amazon RDS for Oracle with minimal downtime. Which AWS service should be used for the initial data load and ongoing replication?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports both full-load migration and ongoing change data capture (CDC) replication from Oracle to Amazon RDS for Oracle. DMS uses Oracle LogMiner or binary reader to capture incremental changes from the source database's redo logs, enabling near-zero downtime migration without requiring application modifications.

Answer

AWS Snowball

Answer

AWS Direct Connect

Answer

AWS Schema Conversion Tool (SCT)

Question 8

A company is deploying a multi-AZ Aurora MySQL database. They need to ensure that failover happens automatically with minimal data loss. Which configuration should be used?

Accepted Answer

Create an Aurora cluster with one primary and two readers in different Availability Zones.. An Aurora cluster with one primary and two readers in different Availability Zones provides automatic failover with minimal data loss. Aurora uses a shared cluster volume that is replicated six ways across three AZs, ensuring that during a failover, the promoted reader has access to all committed transactions with no data loss. This configuration meets the requirement for multi-AZ high availability and automatic failover within a single region.

Answer

Deploy an Aurora Global Database with a primary in one region and a secondary in another region.

Answer

Use a Multi-AZ RDS for MySQL deployment.

Answer

Configure a single-AZ Aurora instance and enable cross-Region replication.

Question 9

A company is migrating a 10 TB PostgreSQL database from on-premises to Amazon RDS for PostgreSQL. They need to minimize downtime and have limited network bandwidth. Which approach is most appropriate?

Accepted Answer

Use AWS Snowball to transfer a physical backup to AWS, then use DMS for ongoing replication.. The 10 TB database size combined with limited network bandwidth makes a direct online migration impractical due to prolonged transfer times. AWS Snowball allows you to physically ship the database backup to AWS, bypassing bandwidth constraints. After loading the backup into Amazon RDS, AWS DMS can perform ongoing change data capture (CDC) replication to synchronize any changes made during the transfer, minimizing downtime.

Answer

Use AWS Database Migration Service (DMS) with a full load and ongoing replication to keep the target in sync.

Answer

Use pg_dump to export the database and pg_restore to import to RDS, then use DMS for replication.

Answer

Use AWS Direct Connect to increase bandwidth and then use DMS for full load and replication.

Question 10

A company wants to migrate an on-premises SQL Server database to Amazon RDS for SQL Server. They need to convert stored procedures and functions. Which AWS service should they use?

Accepted Answer

AWS SCT. AWS SCT (Schema Conversion Tool) is the correct service because it specializes in converting database schemas, including stored procedures and functions, from one engine to another. For migrating on-premises SQL Server to Amazon RDS for SQL Server, SCT can analyze and convert the schema objects, handling syntax differences and compatibility issues automatically.

Answer

AWS CloudEndure Migration

Answer

AWS DMS

Answer

AWS Snowball

Question 11

A company is deploying a new web application that uses Amazon RDS for MySQL. To improve read performance, they add a read replica. However, the application reports stale data. What is the most likely cause?

Accepted Answer

The replication is asynchronous and there is replication lag.. Amazon RDS for MySQL uses asynchronous replication for read replicas. The primary instance commits writes and then sends the binary log (binlog) events to the replica, which applies them. This asynchronous nature introduces replication lag, meaning the replica may not have the most recent writes. If the application reads from the replica before the lag is resolved, it will see stale (older) data.

Answer

The application is using a connection pool that caches connections to the primary.

Answer

The read replica is in a different AWS Region.

Answer

The application is reading from the replica before the write is committed on the primary.

Question 12

A company is migrating a 5 TB MongoDB database to Amazon DocumentDB. They have a short maintenance window and need to minimize downtime. Which migration strategy should be used?

Accepted Answer

Use AWS DMS to perform a full load and then ongoing replication from the source MongoDB.. AWS DMS supports MongoDB as a source and Amazon DocumentDB as a target, enabling a full load of the 5 TB database followed by ongoing change data capture (CDC) using MongoDB's oplog. This minimizes downtime by keeping the target nearly synchronized during the migration window, allowing a final cutover with minimal interruption.

Answer

Use the MongoDB change streams feature to replicate changes to DocumentDB in real time.

Answer

Set up AWS Direct Connect to the source and use mongorestore directly to DocumentDB.

Answer

Export the data using mongodump, transfer to Amazon S3, and import using mongorestore.

Question 13

A company is planning to deploy an Amazon RDS for PostgreSQL instance. Which of the following is a required step to enable automated backups?

Accepted Answer

Set the backup retention period to a value greater than 0.. Automated backups in Amazon RDS for PostgreSQL are enabled by setting a backup retention period greater than 0 days. By default, the retention period is 0, which disables automated backups. Once set to a value between 1 and 35 days, RDS automatically takes daily snapshots and retains transaction logs for point-in-time recovery within that window.

Answer

Set a preferred maintenance window.

Answer

Enable encryption at rest.

Answer

Configure a Multi-AZ deployment.

Question 14

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. They want to use Oracle GoldenGate for replication. Which AWS service can be used to simplify the setup of GoldenGate on AWS?

Accepted Answer

AWS Marketplace. AWS Marketplace offers pre-configured Oracle GoldenGate AMIs that simplify the setup and deployment of GoldenGate on EC2, reducing the manual installation and configuration effort. This is the correct choice because the question asks for a service that simplifies the setup of GoldenGate itself, not the migration tool or infrastructure orchestration.

Answer

AWS DMS

Answer

Amazon RDS for Oracle with GoldenGate enabled

Answer

AWS CloudFormation

Question 15

A company is deploying a new application that requires a globally distributed database with low latency reads. They choose Amazon DynamoDB global tables. What is a key consideration for this deployment?

Accepted Answer

Each replica can serve reads and writes independently.. Amazon DynamoDB global tables use a multi-master, active-active replication model. This means each replica region can independently serve both reads and writes, with eventual consistency across regions. This design enables low-latency local reads and writes for globally distributed applications, as each region operates autonomously.

Answer

Writes are synchronously replicated to all regions.

Answer

The table class must be DynamoDB Standard-Infrequent Access.

Answer

Global tables support strongly consistent reads from any region.