DBS-C01 Practice Test 34 — 15 Questions

Question 1

An IAM policy is attached to a role used by an application to access an Amazon RDS for MySQL DB instance. The DB instance is encrypted with a customer-managed KMS key. The application is unable to create a snapshot of the encrypted DB instance. Which missing permission is the most likely cause?

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

Accepted Answer

kms:CreateGrant. To create a snapshot of an encrypted RDS DB instance, the IAM role must have the kms:CreateGrant permission on the customer-managed KMS key. This permission allows RDS to create a grant that enables it to use the key for encrypting the snapshot. Without kms:CreateGrant, the snapshot creation fails. Options A (kms:ReEncrypt), B (kms:DescribeKey), and D (kms:Encrypt) are not required for this operation.

Answer

kms:ReEncrypt

Answer

kms:DescribeKey

Answer

kms:Encrypt

Question 2

A company is migrating an on-premises MySQL database to Amazon RDS for MySQL. The database has a large table with frequent inserts and updates. To minimize downtime during migration, which AWS service should be used?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports ongoing replication (change data capture, CDC) from an on-premises MySQL source to Amazon RDS for MySQL, allowing the source database to remain fully operational during the migration. This minimizes downtime by continuously applying inserts and updates from the source to the target until you perform the final cutover, which can be a brief pause of seconds to minutes.

Answer

Amazon RDS read replica

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS Glue

Question 3

A company is using Amazon DynamoDB with provisioned capacity. The application is experiencing throttling on write requests. The database specialist needs to identify the cause. Which TWO metrics should be reviewed in CloudWatch? (Select TWO.)

Accepted Answer

ConsumedWriteCapacityUnits. 'ConsumedWriteCapacityUnits' shows the actual write capacity used, helping to determine if provisioned capacity is exceeded, which leads to throttling. Option B is correct because 'WriteThrottleEvents' directly indicates the number of throttled write requests. Option C is incorrect because 'ThrottledWriteRequests' is not a valid CloudWatch metric for DynamoDB; the correct metric for throttled writes is 'WriteThrottleEvents'. Option D is incorrect because 'ReadThrottleEvents' pertains to read throttling, not writes. Option E is incorrect because 'SuccessfulRequestLatency' measures latency, not throttling events.

Answer

ThrottledWriteRequests

Answer

ReadThrottleEvents

Answer

SuccessfulRequestLatency

Question 4

A company runs an Amazon RDS for PostgreSQL DB instance with Multi-AZ enabled. The primary instance is in us-east-1a and the standby is in us-east-1b. During a routine audit, the security team discovers that database connections are being terminated unexpectedly. The database administrator reviews the RDS events and sees an event: 'A Multi-AZ failover has been completed.' What step should be taken to determine the cause of this failover?

Accepted Answer

Review RDS events and AWS CloudTrail logs for API calls related to the failover. A Multi-AZ failover can be triggered by a variety of causes, including an Availability Zone outage, a primary instance failure, a storage failure, or a manual reboot with failover. RDS events provide a timeline of what happened, and CloudTrail logs capture API calls such as RebootDBInstance with ForceFailover, which can indicate human-initiated failovers. Reviewing both is the correct way to determine the cause.

Answer

Examine Amazon CloudWatch metrics for increased CPU or memory usage

Answer

Check the RDS console for maintenance windows

Answer

Run the describe-db-instances CLI command to check the status of the standby

Question 5

A company uses Amazon ElastiCache for Redis as a caching layer for a web application. They observe a sudden increase in CPU utilization on the cache cluster, and the application experiences higher latency. Which action should be taken to diagnose the issue?

Accepted Answer

Monitor Amazon CloudWatch metrics for the ElastiCache cluster to identify the cause.. Amazon CloudWatch provides native metrics for ElastiCache (CPUUtilization, EngineCPUUtilization, CurrConnections, CacheHits/Misses, Evictions, etc.) that allow you to pinpoint the cause of increased CPU and latency, such as a spike in connections, heavy commands, or evictions. Monitoring these metrics is the correct first diagnostic step before making changes.

Answer

Enable query profiling on the ElastiCache cluster.

Answer

Disable persistence to reduce CPU overhead.

Answer

Immediately scale up to a larger node type.

Question 6

A company runs a financial application on Amazon RDS for PostgreSQL that requires point-in-time recovery (PITR) with a recovery point objective (RPO) of 1 second and recovery time objective (RTO) of 5 minutes. Which configuration meets these requirements at the lowest cost?

Accepted Answer

Multi-AZ RDS with synchronous standby.. Multi-AZ RDS for PostgreSQL with synchronous standby replication provides automatic failover to a standby in a different Availability Zone, enabling an RTO of typically 1–2 minutes, well within the 5-minute requirement. Automated backups and transaction logs allow PITR with an RPO of 1 second by restoring to any point within the retention period, and the synchronous standby ensures zero data loss during failover, meeting the strict RPO at the lowest cost for this high-availability need.

Answer

Single-AZ RDS with automated backups and manual snapshot restore.

Answer

Single-AZ RDS with a read replica and promote on failure.

Answer

Single-AZ RDS with cross-region snapshot copy.

Question 7

A company needs to store time-series data from IoT sensors. Each sensor sends a reading every minute. The data is rarely accessed after 30 days. The query pattern is to retrieve all readings for a specific sensor within a time range. Which AWS database is most cost-effective?

Accepted Answer

Amazon Timestream. Amazon Timestream is purpose-built for time-series data, offering automatic tiered storage (in-memory for recent data and magnetic for historical data) and built-in time-series functions. For IoT sensors sending readings every minute with rare access after 30 days, Timestream's cost-effective storage tiering and efficient querying for a specific sensor within a time range make it the most suitable and economical choice.

Answer

Amazon Redshift

Answer

Amazon DynamoDB with Time-to-Live (TTL)

Answer

Amazon RDS for PostgreSQL with partitioning

Question 8

A company is migrating a 10 TB Oracle data warehouse to Amazon Redshift. The migration must minimize data transfer costs and ensure data integrity. Which TWO steps should the company take?

Accepted Answer

Use AWS Schema Conversion Tool (SCT) to convert the Oracle schema to Redshift. The AWS Schema Conversion Tool (SCT) is specifically designed to convert Oracle database schemas to Amazon Redshift-compatible schemas, handling data type mappings, stored procedures, and other schema objects. This step is critical for a successful migration as it ensures the target schema is optimized for Redshift's columnar storage and MPP architecture, reducing manual rework and potential data integrity issues.

Answer

Use AWS DMS to replicate data directly over the internet

Answer

Use Amazon Kinesis Data Streams to stream data to Redshift

Answer

Use Amazon Redshift Spectrum to query data in S3 after loading

Question 9

A company wants to deploy a highly available Amazon RDS for MySQL database across two Availability Zones. Which feature should be enabled?

Accepted Answer

Multi-AZ deployment. Multi-AZ deployment synchronously replicates data to a standby instance in a different Availability Zone, providing automatic failover in case of an AZ outage. This is the correct feature for achieving high availability across two Availability Zones, as it ensures minimal downtime without manual intervention.

Answer

Read replicas in a different AZ

Answer

Automated backups with retention

Answer

Enhanced Monitoring

Question 10

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and has a high transaction rate. The migration must have minimal downtime and support ongoing replication. Which AWS service should be used for the migration?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS is the correct service because it supports ongoing replication (change data capture) from an on-premises Oracle source to Amazon RDS for Oracle, enabling a migration with minimal downtime. It can handle a 2 TB database by using a full load followed by continuous replication of transactions, and it supports Oracle-specific features like supplemental logging and LogMiner for CDC.

Answer

AWS Schema Conversion Tool (AWS SCT)

Answer

AWS Direct Connect

Answer

Amazon RDS Read Replica

Question 11

A company is deploying Amazon DynamoDB for a new application. The application requires single-digit millisecond latency for read operations. Which DynamoDB feature should be configured to meet this requirement?

Accepted Answer

DynamoDB Accelerator (DAX). DynamoDB Accelerator (DAX) is an in-memory caching service that sits between your application and DynamoDB, providing microsecond to single-digit millisecond latency for read-heavy workloads. By caching frequently accessed items, DAX offloads read traffic from the underlying DynamoDB tables, ensuring consistent low-latency responses even under high concurrency.

Answer

DynamoDB Streams

Answer

Auto Scaling

Answer

Time to Live (TTL)

Question 12

A company is designing a global application that requires a database with multi-master writes across multiple AWS Regions with sub-second conflict resolution. Which AWS database service should they choose?

Accepted Answer

Amazon DynamoDB Global Tables. Amazon DynamoDB Global Tables is the correct choice because it provides a fully managed, multi-Region, multi-master database that replicates data across AWS Regions with sub-second conflict resolution using last-writer-wins (LWW) or application-defined conflict resolution. This meets the requirement for multi-master writes and sub-second conflict resolution, which is not achievable with the other options.

Answer

Amazon ElastiCache for Redis Global Datastore

Answer

Amazon RDS with Multi-AZ

Answer

Amazon Aurora Global Database

Question 13

A company is using Amazon DynamoDB and wants to ensure that all data is automatically encrypted at rest. What is the default encryption status for a new DynamoDB table?

Accepted Answer

Encryption is enabled by default using an AWS-owned key.. Amazon DynamoDB encrypts all data at rest by default using an AWS-owned key managed by the service, with no configuration required from the customer. This default encryption covers tables, indexes, and backups, and it happens transparently without impacting performance or requiring key management on the customer side.

Answer

Encryption is optional and can be enabled during table creation.

Answer

Encryption is disabled by default and must be enabled manually.

Answer

Encryption is enabled by default using a customer-managed key.

Question 14

A database administrator needs to monitor the number of database connections to an Amazon RDS for PostgreSQL instance. Which Amazon CloudWatch metric should the administrator use?

Accepted Answer

DatabaseConnections. The correct metric is `DatabaseConnections`, which is published by Amazon RDS for PostgreSQL to CloudWatch. It reports the number of client network connections to the database instance, corresponding to the `numbackends` value from the `pg_stat_database` view. This metric directly reflects the current connection count and is the standard way to monitor connection usage for RDS PostgreSQL.

Answer

ActiveConnections

Answer

ConnectionsCount

Answer

DBInstanceIdentifier

Question 15

A company wants to store database credentials for an Amazon RDS instance securely. Which AWS service should be used to rotate the credentials automatically?

Accepted Answer

AWS Secrets Manager. AWS Secrets Manager is the correct service because it can automatically rotate database credentials for Amazon RDS, simplifying credential management and improving security. AWS Systems Manager Parameter Store can store parameters but does not natively rotate RDS credentials. AWS IAM roles are used for authentication and authorization, not for storing credentials. AWS CloudHSM provides hardware security module (HSM) for encryption key management, not credential storage or rotation.

Answer

AWS CloudHSM

Answer

AWS Systems Manager Parameter Store

Answer

AWS IAM roles