DBS-C01 Management and Operations Practice Test 6 — 15 Questions

Question 1

A company uses Amazon ElastiCache for Redis as a caching layer for its e-commerce application. Recently, the cache hit ratio has dropped significantly, causing increased database load. The operations team needs to identify which cache keys are being evicted. What should they do?

Accepted Answer

Monitor the 'Evictions' metric in Amazon CloudWatch for the ElastiCache cluster.. Option B is correct because the 'evictions' metric in CloudWatch shows the number of evicted keys, and enabling the 'Evicted' statistic can help monitor evictions. Option A is incorrect because the INFO command shows current evictions but not historical trends. Option C is incorrect because ElastiCache events do not include eviction details. Option D is incorrect because slow-log shows slow commands, not evictions.

Answer

Check the ElastiCache event history for eviction events.

Answer

Enable the 'INFO' command output to be logged to CloudWatch Logs.

Answer

Enable the Redis slow-log to capture eviction commands.

Question 2

A developer needs to restore an Amazon RDS for PostgreSQL DB instance to a specific point in time within the retention period. What must be enabled for this operation to be possible?

Accepted Answer

Automated backups with a retention period greater than 0.. Option A is correct because automated backups (enabled by default with a retention period) are required for point-in-time recovery (PITR). Option B is incorrect because Multi-AZ is not required for PITR. Option C is incorrect because read replicas are not needed. Option D is incorrect because deletion protection prevents accidental deletion but does not affect PITR.

Answer

Deletion protection enabled.

Answer

A read replica in the same region.

Answer

Multi-AZ deployment.

Question 3

A company is running a MongoDB-compatible Amazon DocumentDB cluster. The application is experiencing high write latency during peak hours. The cluster has one writer and two readers. The DBA suspects that the issue is due to a large number of indexes on the collection. What should the DBA do to verify this hypothesis without affecting production?

Accepted Answer

Create a clone of the cluster using the 'Clone Cluster' feature and test index changes on the clone.. Option D is correct because creating a clone of the cluster in the same account allows testing in an isolated environment without impacting production. Option A is incorrect because using the profiler to identify slow queries does not directly test the impact of indexes. Option B is incorrect because AWS DMS is used for migration, not for testing index impact. Option C is incorrect because restoring a snapshot into a new cluster is disruptive as it requires taking a snapshot and restoring, which can be time-consuming and does not provide real-time data.

Answer

Take a snapshot of the cluster and restore it to a new cluster to test index changes.

Answer

Use AWS DMS to replicate data to a test cluster and perform index testing there.

Answer

Enable the profiler on the production cluster to capture slow queries and analyze the index usage.

Question 4

A company is using Amazon DynamoDB with on-demand capacity. The operations team wants to monitor for throttled requests. Which TWO metrics from Amazon CloudWatch should be used to set up an alarm for throttling? (Select TWO.)

Accepted Answer

ThrottledPutRecords. Options A and B are correct. 'ThrottledGetRecords' and 'ThrottledPutRecords' are CloudWatch metrics that directly indicate throttled read and write requests. Option C is incorrect because 'ReadThrottleEvents' is not a standard DynamoDB metric. Option D is incorrect because 'ProvisionedReadCapacityUnits' is for provisioned mode. Option E is incorrect because 'ConsumedWriteCapacityUnits' shows consumed capacity, not throttling.

Answer

ConsumedWriteCapacityUnits

Answer

ReadThrottleEvents

Answer

ProvisionedReadCapacityUnits

Question 5

A database administrator is responsible for managing an Amazon RDS for Oracle DB instance. The DBA needs to ensure that all changes to the DB instance's security group rules are logged for audit purposes. Which TWO services can be used together to achieve this? (Select TWO.)

Accepted Answer

AWS CloudTrail. Options A and B are correct. AWS CloudTrail logs API calls, including those that modify security group rules (e.g., AuthorizeSecurityGroupIngress). CloudTrail logs can be sent to Amazon CloudWatch Logs for monitoring and alerting. Option C is incorrect because AWS Config tracks configuration changes but does not provide real-time log streaming to CloudWatch Logs. Option D is incorrect because VPC Flow Logs capture network traffic, not API calls. Option E is incorrect because Amazon Inspector is for security assessments.

Answer

Amazon Inspector

Answer

AWS Config

Answer

Amazon VPC Flow Logs

Question 6

A company is migrating its on-premises PostgreSQL database to Amazon Aurora PostgreSQL. The migration must have minimal downtime. Which THREE steps should be taken as part of the migration plan? (Select THREE.)

Accepted Answer

Perform a test migration to validate the process.. Options A, B, and C are correct. Setting up replication from the on-premises database to Aurora using AWS DMS with ongoing replication allows the target to stay up-to-date with minimal downtime. Performing a test migration ensures the process works. After the cutover, the application connection string must be updated. Option D is incorrect because disabling automated backups is not recommended; backups are essential. Option E is incorrect because enabling Multi-AZ is for high availability, not a migration step.

Answer

Enable Multi-AZ on the Aurora cluster before migration.

Answer

Disable automated backups on the Aurora cluster to improve performance.

Question 7

A company is using a Multi-AZ RDS for MySQL instance. The primary instance recently experienced an unexpected failover, and the application experienced a brief interruption. The database administrator wants to investigate the root cause. Which AWS service should be used to review the failover event and its details?

Accepted Answer

AWS Support (Trusted Advisor). AWS Support provides detailed logs and analysis for events like failovers through the AWS Support API and AWS Support Center. CloudTrail records API calls, RDS events show notifications but not deep root cause analysis, and Config tracks configuration changes. The correct service for RCA is AWS Support.

Answer

AWS Config

Answer

Amazon RDS Event Notifications

Answer

AWS CloudTrail

Question 8

A company runs a production Amazon RDS for PostgreSQL database with automated backups enabled. A database administrator accidentally dropped a critical table. The administrator wants to restore the table from a point in time before the drop. The database is 1 TB in size and the recovery point objective (RPO) is 5 minutes. Which approach minimizes downtime?

Accepted Answer

Use the point-in-time recovery feature to restore the database to a new DB instance at a time before the drop, then use pg_dump to export the table and import it into the production database.. Point-in-time recovery (PITR) to a new DB instance is the most efficient way to restore a specific table without affecting the existing production database. Restoring to the existing instance would cause downtime. pg_dump from a read replica is slower and not point-in-time. Manual backup from S3 is not automated and not point-in-time.

Answer

Restore the automated backup from S3 to a new EC2 instance running PostgreSQL, then export the table and import it into the production database.

Answer

Restore the database from the most recent manual snapshot to a new instance, then use pg_dump to extract the table and import it into the production database.

Answer

Create a read replica from the production database, stop replication, and use pg_dump to extract the table from the replica and import it into the production database.

Question 9

A company needs to ensure that all changes to an Amazon RDS DB instance's security group are logged for auditing purposes. Which AWS service should be enabled?

Accepted Answer

AWS CloudTrail. AWS CloudTrail records API calls made to the AWS environment, including changes to security groups. RDS event subscriptions are for database events, not API calls. Config tracks configuration changes but is not primarily for API logging. VPC Flow Logs capture network traffic, not API calls.

Answer

Amazon RDS Event Subscriptions

Answer

AWS Config

Answer

VPC Flow Logs

Question 10

A company has a production Amazon Aurora MySQL DB cluster with one writer and two reader instances. The application uses a custom connection pool that uses the writer endpoint for all database calls. The application is experiencing increased latency during peak hours. A database specialist suggests using the reader endpoint for read-only queries. What change is required on the application side to implement this recommendation?

Accepted Answer

Update the application's connection logic to use the cluster endpoint for writes and the reader endpoint for reads.. The application needs to differentiate between read and write queries and send read queries to the reader endpoint while write queries continue to use the writer endpoint. No changes to the Aurora cluster are needed; Aurora automatically handles connectivity to reader instances via the reader endpoint. The cluster endpoint remains unchanged for writes.

Answer

Modify the Aurora cluster to enable load balancing for the reader endpoint.

Answer

Create a new custom endpoint for read-only queries and use it instead of the reader endpoint.

Answer

Replace the writer endpoint with the reader endpoint in the connection pool configuration.

Question 11

A database administrator is troubleshooting a performance issue on an Amazon RDS for SQL Server instance. The CPU utilization is consistently above 90%, and the number of database connections is high. Which Amazon CloudWatch metric should be analyzed first to determine if the issue is due to a specific query?

Accepted Answer

Enhanced Monitoring (cpuUtilization per process). While CloudWatch provides metrics like CPUUtilization, the question asks for a metric that helps identify a specific query causing high CPU. CloudWatch does not directly expose query-level metrics; however, enhanced monitoring provides OS-level metrics but not query details. To identify specific queries, you need to use RDS Performance Insights or SQL Server's own DMVs. Among the options, 'DatabaseConnections' is not query-specific. The correct answer is to use Performance Insights, but since it's not listed, the best CloudWatch metric is 'CPUUtilization' to confirm high CPU, but the actual tool for query analysis is not CloudWatch. The question expects 'Enhanced Monitoring' as it gives per-process metrics that can lead to identifying queries if combined with other tools. However, none directly identify a specific query. The closest is Enhanced Monitoring which can show top processes. 'DatabaseConnections' does not help. The correct answer is D because Enhanced Monitoring provides OS-level metrics that can help pinpoint resource-intensive processes that may be running specific queries.

Answer

DatabaseConnections

Answer

ReadIOPS

Answer

CPUUtilization

Question 12

A company has an Amazon RDS for MySQL DB instance that is running low on storage. The current allocated storage is 500 GB, and the free space is down to 10 GB. The database administrator wants to increase storage with minimal downtime. Which action should be taken?

Accepted Answer

Use the AWS Management Console to modify the DB instance and increase the allocated storage.. RDS supports modifying storage online with minimal downtime. Increasing allocated storage from 500 GB to, for example, 600 GB can be done via a modification to the DB instance. The instance remains available during the modification, though a brief performance impact may occur. Stopping the instance is unnecessary. Creating a snapshot and restoring would cause longer downtime. Waiting for autoscaling might not be quick enough if space is critically low.

Answer

Stop the DB instance, modify the allocated storage, and start the instance.

Answer

Create a snapshot of the current DB instance, restore it to a new larger instance, and point the application to the new endpoint.

Answer

Enable storage autoscaling and wait for the automatic increase.

Question 13

A company uses Amazon DynamoDB with on-demand capacity mode for a critical application. During a marketing campaign, the application experienced throttled requests despite the on-demand mode. The table has a single partition key. The database specialist notices that the throttling occurs sporadically even though overall traffic is within limits. What is the most likely cause?

Accepted Answer

The table's partition key is causing a hot partition, leading to throttling on that partition.. On-demand mode accommodates traffic spikes, but if a single partition key is used, all traffic goes to one partition. DynamoDB partitions data by partition key; a single hot key can throttle requests even if overall throughput is within limits. Provisioned capacity is not used. Auto scaling is not relevant. The partition limit is a hard limit.

Answer

The table's provisioned capacity is set too low.

Answer

The table's auto scaling is not configured correctly.

Answer

The application is exceeding the DynamoDB account-level throughput limits.

Question 14

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size. The company wants to minimize downtime during the migration. Which AWS service should be used to perform an online migration with minimal downtime?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) supports ongoing replication to minimize downtime. Snowball is for offline data transfer. S3 is not a migration service. Direct Connect provides a dedicated network connection but is not a migration service itself.

Answer

AWS Direct Connect

Answer

AWS Snowball

Answer

Amazon S3

Question 15

A database administrator needs to retain backups of an Amazon RDS for PostgreSQL DB instance for 7 years to meet compliance requirements. The automated backup retention period is limited to 35 days. Which solution should be used?

Accepted Answer

Create manual snapshots at regular intervals and retain them for 7 years.. Manual snapshots are retained indefinitely until deleted. Automated backups have a max retention of 35 days. Exporting to S3 is an option but not directly a backup retention method; you can export snapshots to S3, but manual snapshots are the standard way to retain backups long-term. EC2 instance backups are not applicable.

Answer

Export the automated backups to Amazon S3 and apply an S3 lifecycle policy.

Answer

Increase the automated backup retention period to 7 years.

Answer

Use an AWS Lambda function to copy automated backups to an EC2 instance.