DBS-C01 Practice Test 8 — 10 Questions

Question 1

What is the purpose of the 'TimeToLiveSpecification' in this template?

Accepted Answer

It enables DynamoDB to automatically delete items after the specified timestamp. The 'TimeToLiveSpecification' in an AWS DynamoDB CloudFormation template enables DynamoDB's Time to Live (TTL) feature, which automatically deletes items when the current time exceeds the epoch timestamp value stored in the specified attribute (e.g., 'expire_time'). This is a cost-effective way to manage data retention without requiring custom delete logic or additional write capacity.

Answer

It enforces that the 'expire_time' attribute must be unique

Answer

It automatically updates the 'expire_time' attribute when an item is read

Answer

It creates a backup of items that have expired

Question 2

A developer needs to grant an IAM user the ability to perform all operations on an Amazon RDS DB instance except the ability to delete it. Which IAM policy action should be explicitly denied?

Accepted Answer

rds:DeleteDBInstance. To prevent deletion, you must explicitly deny the rds:DeleteDBInstance action. Option A (rds:RebootDBInstance) is incorrect because it only reboots the instance. Option B (rds:StopDBInstance) is incorrect because it only stops the instance. Option C (rds:ModifyDBInstance) is incorrect because it only modifies the instance. Option D (rds:DeleteDBInstance) is the correct action to deny to prevent deletion.

Answer

rds:RebootDBInstance

Answer

rds:StopDBInstance

Answer

rds:ModifyDBInstance

Question 3

A company is migrating a MySQL database to Amazon RDS for MySQL. They want to use AWS DMS for continuous replication. Which TWO prerequisites must be met before starting the migration?

Accepted Answer

Enable binary logging (binlog) on the source MySQL database.. Option A is correct because AWS DMS requires binary logging (binlog) to be enabled on the source MySQL database for continuous replication (change data capture); the binlog_format must be set to ROW and the retention period long enough to cover the migration. Option B is correct because the DMS replication instance must have network connectivity to both the source and target databases, typically via VPC security groups, subnets, and routing, otherwise the endpoints cannot be reached and the task will fail. Option C is not required because DMS performs ongoing replication without forcing the source into read-only mode; writes can continue while changes are captured from the binlog. Option D is not a prerequisite because the source database can reside on-premises or outside a VPC, as long as connectivity to the replication instance is established. Option E is not required because DMS logs are written to Amazon CloudWatch Logs, not to an S3 bucket created for migration logs.

Answer

Set the source database to read-only mode during migration.

Answer

Place the source database in a VPC.

Answer

Create an S3 bucket to store the migration logs.

Question 4

A company is launching a new application that requires an Amazon RDS for PostgreSQL database. The database will store highly sensitive data, and the security team mandates that all data at rest must be encrypted. The company also requires that the encryption keys be managed by the security team using AWS CloudHSM. What is the MOST efficient way to meet these requirements?

Accepted Answer

Use AWS KMS with a customer-managed key (CMK) for RDS encryption.. RDS encryption at rest is always performed using AWS KMS keys. To have the security team manage keys via CloudHSM, you create a KMS customer-managed key (CMK) backed by a CloudHSM custom key store, then select that CMK when creating the RDS instance. This satisfies both the encryption-at-rest mandate and the CloudHSM key-management requirement without application changes.

Answer

Enable EBS encryption on the RDS instance's underlying volumes using a KMS key.

Answer

Enable Transparent Data Encryption (TDE) using a CloudHSM key in the RDS instance.

Answer

Implement client-side encryption in the application before writing data to the database.

Question 5

A company is designing a multi-region active-active application that requires low-latency reads and writes across regions. The database must support conflict resolution. Which database should be used?

Accepted Answer

Amazon DynamoDB Global Tables. Amazon DynamoDB Global Tables is the correct choice because it provides a fully managed, multi-region, multi-active database that replicates data across regions with eventual consistency, supporting low-latency reads and writes. It includes built-in conflict resolution using a last-writer-wins (LWW) mechanism based on timestamps, which meets the requirement for conflict resolution in an active-active architecture.

Answer

Amazon RDS Multi-AZ

Answer

Amazon Redshift

Answer

Amazon Aurora Global Database

Question 6

Arrange the steps to migrate an on-premises Oracle database to Amazon RDS for Oracle using AWS DMS (Database Migration Service) in the correct order.

Accepted Answer

Launch the DMS replication instance, then configure the source and target endpoints, then create the migration task, then monitor the migration task.. DMS migration requires setting up the replication instance, configuring endpoints with proper source database settings for CDC, creating a migration task, and monitoring for completion.

Answer

Configure the source and target endpoints, then launch the DMS replication instance, then create the migration task, then monitor the migration task.

Answer

Launch the DMS replication instance, then create the migration task, then configure the source and target endpoints, then monitor the migration task.

Answer

Configure the source and target endpoints, then launch the DMS replication instance, then monitor the migration task, then create the migration task.

Question 7

A company is designing a multi-tenant application using Amazon Aurora MySQL. Each tenant's data must be isolated from others. They need to encrypt data at rest with a unique AWS KMS key per tenant. How can this be achieved?

Accepted Answer

Launch separate Aurora clusters for each tenant, each with its own KMS key for encryption at rest.. To encrypt each tenant's data with a unique KMS key, you must launch separate Aurora clusters for each tenant, because encryption at rest is applied at the cluster level using a single KMS key. Each cluster can be configured with its own KMS key, providing tenant isolation. This approach ensures that data for each tenant is encrypted with a distinct key.

Answer

Create separate databases within the same Aurora cluster and assign a different KMS key to each database.

Answer

Use client-side encryption with different KMS keys per tenant before inserting data into the database.

Answer

Use a single Aurora cluster with row-level encryption using different KMS keys per tenant.

Question 8

Refer to the exhibit. A database engineer runs the query above to troubleshoot an application error. The query returns no results even though the database is generating errors. What is the most likely reason?

Accepted Answer

The log stream format uses a different field name for the error message. The most likely reason the query returns no results is that the log stream format uses a different field name for the error message than the one referenced in the query. In CloudWatch Logs Insights, the query must reference fields exactly as they appear in the log events. If the logs use a different key (e.g., 'message' vs 'errorMessage'), the filter will not match.

Answer

The regex pattern does not match because it is case-sensitive

Answer

The query does not specify a time range, so no results are returned

Answer

The log group has not been configured to export to CloudWatch Logs

Question 9

A company is migrating an on-premises Microsoft SQL Server database to Amazon RDS for SQL Server. The database supports a line-of-business application that requires high availability and automatic failover within a single AWS Region. The company wants to minimize downtime during the migration and ensure that the database can automatically recover from an Availability Zone failure. Which feature should the company implement?

Accepted Answer

Multi-AZ deployment with a standby replica in another Availability Zone. For Amazon RDS for SQL Server, Multi-AZ deployment provides a synchronous standby replica in a different Availability Zone and automatic failover in case of an AZ failure. This is the standard high availability feature offered by RDS. Read replicas are for read scaling and do not provide automatic failover. AWS DMS is for migration. Always On Availability Groups are supported but require additional configuration and are not the primary RDS high availability feature. Therefore, Multi-AZ deployment is the correct choice.

Answer

AWS Database Migration Service (AWS DMS) with ongoing replication

Answer

Amazon RDS for SQL Server with Always On Availability Groups

Answer

Read replicas in multiple Availability Zones

Question 10

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.