DBS-C01 Management and Operations Practice Test 2 — 15 Questions

Question 1

A company runs a critical e-commerce application on Amazon RDS for PostgreSQL with a db.r5.2xlarge instance and 500 GB of gp2 storage. The application experiences periodic write spikes during flash sales. During these events, the WriteIOPS metric exceeds the provisioned baseline IOPS of 1,500, and the database becomes unresponsive for several seconds. The DBA has configured a CloudWatch alarm on WriteIOPS, but the alarm triggers after the performance issue occurs. The company needs to ensure that the database can handle these spikes without downtime. The budget allows for moderate cost increases. What should the DBA do?

Accepted Answer

Modify the DB instance to use gp3 storage with provisioned IOPS of 5,000.. Option B is correct because gp3 storage provides a baseline of 3,000 IOPS regardless of storage size, and allows provisioning up to 16,000 IOPS independently. By setting provisioned IOPS to 5,000, the database can handle write spikes without exceeding the IOPS limit, preventing unresponsiveness. This solution fits the moderate cost increase budget, as gp3 is typically 20% cheaper than gp2 for equivalent performance.

Answer

Increase the allocated storage to 1,000 GB to increase baseline IOPS to 3,000.

Answer

Enable Performance Insights to identify the problematic queries and tune them.

Answer

Add a read replica and redirect read traffic to it to reduce write contention.

Question 2

A company runs a production Amazon RDS for MySQL Multi-AZ DB instance with 10 TB of storage. The application team notices that database write latency has increased from 5 ms to 80 ms over the past week. The DB instance is a db.r5.8xlarge with 500 GB of gp2 storage. CloudWatch metrics show WriteIOPS averaging 10,000, WriteThroughput at 50 MB/s, and BurstBalance decreasing from 100% to 20% over the same period. The DB instance has no reserved IOPS. The database workload is write-heavy with frequent small transactions. The company needs to resolve the high write latency while minimizing costs and downtime. Which solution should the database specialist recommend?

Accepted Answer

Modify the DB instance to increase the allocated storage to 1 TB using gp2, allowing the volume to operate with higher baseline IOPS and burst credits.. Option D is correct because increasing gp2 storage from 500 GB to 1 TB raises the baseline IOPS from 1,500 (3 IOPS/GB) to 3,000, and also increases the burst credit pool size. With WriteIOPS averaging 10,000, the volume is depleting burst credits faster than they can be replenished, causing BurstBalance to drop to 20% and latency to spike. Doubling the storage provides a higher baseline and more credits, reducing reliance on burst and resolving the latency issue without changing instance class or adding cost for reserved IOPS.

Answer

Create a read replica to offload write traffic to the replica and use it for failover.

Answer

Upgrade the DB instance to a db.r5.16xlarge with more vCPUs and memory to handle higher write throughput.

Answer

Enable Performance Insights to identify slow queries and add database-level caching to reduce write load.

Question 3

A company runs a production Amazon RDS for PostgreSQL DB instance. The database experiences intermittent high latency during peak hours. The company's monitoring shows that CPU utilization is below 40%, memory is adequate, and network throughput is normal. The DB instance uses General Purpose SSD (gp2) storage with 3,000 Provisioned IOPS. Which TWO actions should a database specialist take to diagnose and resolve the performance issue? (Choose two.)

Accepted Answer

Check the Burst Balance metric in Amazon CloudWatch for the DB instance.. Option A is correct because gp2 storage uses a credit-based burst model, and the Burst Balance metric indicates the remaining I/O credits. If the burst balance is depleted, the instance is throttled to the baseline IOPS (3,000 for this size), causing high latency despite low CPU and adequate memory. Checking this metric directly identifies whether the storage is starved for I/O credits.

Answer

Change the storage type to Provisioned IOPS SSD (io1) with 10,000 IOPS.

Answer

Increase the Read IOPS by modifying the instance to a larger instance class.

Answer

Review the SwapUsage metric for the DB instance to check for memory pressure.

Question 4

A database specialist sees the above error log entries from an Amazon RDS for MySQL DB instance. Which action should be taken to resolve the issue?

Accepted Answer

Restore the DB instance from the latest automated snapshot.. The error log entries indicate corruption in the InnoDB tablespace, likely due to a crash or hardware failure. Restoring from the latest automated snapshot is the correct action because it provides a consistent, point-in-time recovery of the entire database, including all table structures and data, without relying on potentially corrupted files. This approach ensures data integrity and avoids further damage that could occur from attempting repairs on a corrupted instance.

Answer

Increase the allocated storage for the DB instance.

Answer

Reboot the DB instance to clear the error.

Answer

Run the mysqlcheck command to repair the corrupted tables.

Question 5

A company is migrating its on-premises Oracle database to Amazon RDS for Oracle. The database is 2 TB in size and contains both transactional and analytical workloads. The company uses Oracle Data Pump for migration. During the migration, the database specialist notices that the export job on the source database is taking longer than expected and is generating significant I/O, impacting production performance. The company needs to minimize the impact on the source database while completing the migration within a 48-hour window. The source database is currently running on a dedicated server with sufficient CPU and memory. Which course of action should the database specialist take?

Accepted Answer

Use Oracle Data Pump in network_link mode to directly import the data from the source to the target RDS instance without intermediate files.. Option C is correct because Oracle Data Pump's network_link mode allows the source database to export data directly to the target RDS for Oracle instance over a database link, bypassing the need to write intermediate dump files to disk. This eliminates the I/O overhead on the source server's storage subsystem, which is the primary cause of the production performance impact, while still completing the migration within the 48-hour window.

Answer

Use AWS Database Migration Service (AWS DMS) with full load and change data capture (CDC) to migrate the database.

Answer

Use Data Pump to export to a networked file system (NFS) mount point to offload storage I/O to the network.

Answer

Increase the parallel workers for the Data Pump export job to 8 to speed up the export and reduce the time window.

Question 6

Arrange the steps to perform a point-in-time recovery (PITR) for an Amazon RDS for MySQL DB instance in the correct order.

Question 7

Arrange the steps to switch over from a primary Amazon RDS for Oracle DB instance to a standby in a Multi-AZ deployment (planned failover) in the correct order.

Question 8

Match each AWS database feature to its description.

Question 9

Match each AWS monitoring tool to its capability for databases.

Question 10

A company is running an Amazon RDS for MySQL DB instance. The DB instance is experiencing high CPU utilization due to a sudden increase in read traffic. The company needs to reduce the load on the primary DB instance with minimal downtime. Which solution should be used?

Accepted Answer

Create an RDS read replica and redirect read queries to it.. Option A is correct because creating a read replica offloads read traffic from the primary instance, reducing CPU utilization, and replicas can be promoted later if needed. Option B is wrong because modifying the DB instance class requires downtime. Option C is wrong because Multi-AZ is for high availability, not read scaling. Option D is wrong because caching alone may not reduce CPU utilization caused by database queries.

Answer

Modify the DB instance to a larger instance class.

Answer

Use an Amazon ElastiCache cluster to cache frequent queries.

Answer

Enable Multi-AZ on the DB instance.

Question 11

A company is using Amazon DynamoDB for a gaming application. During a new game launch, write traffic spikes and some users receive 'ProvisionedThroughputExceededException' errors. The company wants to handle these spikes automatically and cost-effectively. What should be done?

Accepted Answer

Enable DynamoDB auto scaling with a target utilization of 70%.. Option B is correct because DynamoDB auto scaling adjusts capacity based on actual traffic patterns, preventing throttling while optimizing cost. Option A is wrong because application-level queuing adds latency. Option C is wrong because on-demand mode is cost-inefficient for predictable spikes. Option D is wrong because increasing provisioned capacity manually is not automatic.

Answer

Implement application-level retries with exponential backoff and a queue.

Answer

Switch the table to on-demand capacity mode.

Answer

Increase the provisioned write capacity to the expected peak.

Question 12

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

Accepted Answer

DatabaseConnections. Option B is correct because 'DatabaseConnections' is the CloudWatch metric that tracks the number of client connections to the DB instance. Option A is wrong because 'CPUUtilization' measures CPU usage. Option C is wrong because 'FreeableMemory' tracks available memory. Option D is wrong because 'WriteLatency' measures write I/O latency.

Answer

CPUUtilization

Answer

WriteLatency

Answer

FreeableMemory

Question 13

A company is using Amazon Aurora MySQL-Compatible Edition. The database is experiencing performance degradation due to long-running queries. The DBA needs to identify the queries that are consuming the most resources. Which action should be taken?

Accepted Answer

Use Amazon RDS Performance Insights to identify the top SQL queries.. Option C is correct because Performance Insights provides a dashboard to analyze database performance and identify top SQL queries by load. Option A is wrong because RDS Enhanced Monitoring shows OS metrics, not specific queries. Option B is wrong because CloudWatch Logs collects logs but does not analyze query performance. Option D is wrong because the slow query log must be enabled and analyzed separately.

Answer

Enable Enhanced Monitoring and review the OS process list.

Answer

Enable the slow query log and use a third-party tool to analyze it.

Answer

Enable CloudWatch Logs for the DB instance and search for errors.

Question 14

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database size is 2 TB and the network bandwidth is limited. The company needs to minimize downtime during migration. Which AWS service should be used?

Accepted Answer

AWS Database Migration Service (DMS). Option D is correct because AWS DMS can perform live migration with minimal downtime. Option A is wrong because AWS SCT helps with schema conversion but not data migration. Option B is wrong because Export/Import from Oracle dump requires downtime. Option C is wrong because AWS Snowball is for offline data transfer, which introduces downtime.

Answer

Oracle Data Pump export and import

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS Snowball Edge

Question 15

A company has an Amazon DynamoDB table with on-demand capacity mode. The table is used by a serverless application. The company wants to receive an alert when the read request rate exceeds a certain threshold. Which CloudWatch metric and alarm should be used?

Accepted Answer

Alarm on the 'ConsumedReadCapacityUnits' metric.. Option A is correct because 'ConsumedReadCapacityUnits' tracks the number of read capacity units consumed, and an alarm can be set on this metric. Option B is wrong because 'ProvisionedReadCapacityUnits' is only for provisioned mode. Option C is wrong because 'ReadThrottleEvents' indicates throttling, not request rate. Option D is wrong because 'SuccessfulRequestLatency' measures latency, not request rate.

Answer

Alarm on the 'ReadThrottleEvents' metric.

Answer

Alarm on the 'ProvisionedReadCapacityUnits' metric.

Answer

Alarm on the 'SuccessfulRequestLatency' metric.