DBS-C01 Management and Operations Practice Test 3 — 15 Questions

Question 1

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?

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

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.. 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 2

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

Accepted Answer

Identify the desired recovery time, then initiate the restore operation specifying the source DB instance and target time, then monitor the restore progress until the new DB instance is available, then verify the data in the restored instance.. PITR restores the database to a specific time within the backup retention window by selecting the restore option and specifying the time.

Answer

Identify the desired recovery time, then monitor the restore progress, then initiate the restore, then verify the data.

Answer

Initiate the restore operation, then identify the desired recovery time, then monitor the restore progress, then verify the data.

Answer

Identify the desired recovery time, then initiate the restore, then verify the data, then monitor the restore progress.

Question 3

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.

Accepted Answer

First verify the standby replica is healthy and in sync, then initiate the failover using the AWS Management Console or CLI, and finally confirm that the new primary is accepting connections.. Planned failover involves verifying standby health, initiating failover, and confirming connectivity.

Answer

First initiate the failover, then verify the standby replica is healthy and in sync, and finally confirm that the new primary is accepting connections.

Answer

First confirm that the new primary is accepting connections, then verify the standby replica is healthy and in sync, and finally initiate the failover.

Answer

First verify the standby replica is healthy and in sync, then confirm that the new primary is accepting connections, and finally initiate the failover.

Question 4

Match each AWS database feature to its description.

Accepted Answer

Multi-AZ: Provides high availability by automatically replicating data to a standby instance in a different Availability Zone.. Multi-AZ is for high availability and failover; Read Replicas offload read traffic; Auto Scaling adjusts capacity; Point-in-Time Recovery enables granular restores. Common confusions involve swapping Multi-AZ and Read Replicas definitions.

Answer

Multi-AZ: Allows you to offload read traffic from the primary database.

Answer

Read Replicas: Provides high availability by automatically replicating data to a standby instance.

Question 5

Match each AWS monitoring tool to its capability for databases.

Accepted Answer

Amazon CloudWatch: Monitors AWS resources and applications, provides metrics and logs. Correct matches: CloudWatch monitors metrics and logs, Performance Insights analyzes database load, Enhanced Monitoring provides OS-level metrics, and CloudTrail records API activity. Common confusions include mixing Enhanced Monitoring with CloudWatch and Performance Insights with CloudTrail.

Answer

Amazon CloudWatch: Provides OS-level metrics for RDS instances

Answer

Amazon RDS Performance Insights: Records API calls for database actions

Question 6

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.. Creating an Amazon RDS read replica allows you to offload read traffic from the primary DB instance to one or more read replicas, which can handle SELECT queries. This reduces CPU utilization on the primary instance with minimal downtime, as read replicas are asynchronous replicas that can be promoted to a primary if needed. Redirecting read queries to the read replica effectively distributes the load without requiring a change to the primary instance's configuration.

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 7

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%.. DynamoDB auto scaling with a target utilization of 70% allows the table to automatically adjust provisioned write capacity in response to traffic spikes, handling the increased load without manual intervention. This approach is cost-effective as it scales down during low traffic periods, avoiding over-provisioning. The target utilization of 70% provides a buffer to absorb sudden spikes while maintaining performance.

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 8

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. The DatabaseConnections metric in Amazon CloudWatch directly reports the number of client connections to the RDS for PostgreSQL DB instance. This metric is published by the RDS service and reflects the count of active connections as seen by the database engine, making it the correct choice for monitoring connection counts.

Answer

CPUUtilization

Answer

WriteLatency

Answer

FreeableMemory

Question 9

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.. Amazon RDS Performance Insights is the correct tool for this scenario because it provides a built-in, easy-to-use dashboard that visualizes database load and identifies the top SQL queries consuming the most resources, such as CPU, I/O, and wait events. Unlike other options, Performance Insights directly correlates database performance metrics with specific queries, enabling the DBA to quickly pinpoint long-running or resource-intensive queries without additional setup or third-party tools.

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 10

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). AWS DMS is the correct choice because it supports ongoing replication from Oracle to Amazon RDS for Oracle, allowing you to perform a live migration with minimal downtime. With a 2 TB database and limited bandwidth, DMS can use Change Data Capture (CDC) to keep the target synchronized while the initial full load runs, then switch over with only a brief outage. This makes it ideal for minimizing downtime compared to offline methods.

Answer

Oracle Data Pump export and import

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS Snowball Edge

Question 11

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.. The 'ConsumedReadCapacityUnits' metric reflects the actual number of read capacity units consumed by the table. By setting an alarm on this metric, you can trigger an alert when the read request rate exceeds a defined threshold, which is appropriate for an on-demand table where capacity scales automatically but you still want to monitor usage.

Answer

Alarm on the 'ReadThrottleEvents' metric.

Answer

Alarm on the 'ProvisionedReadCapacityUnits' metric.

Answer

Alarm on the 'SuccessfulRequestLatency' metric.

Question 12

A company is running Amazon Redshift for data warehousing. The data warehouse is used for complex analytical queries. Recently, query performance has degraded due to data skew. Which steps should be taken to address this issue?

Accepted Answer

Re-evaluate the distribution style of the tables.. Data skew in Amazon Redshift occurs when data is unevenly distributed across slices, causing some nodes to process more data than others and degrading query performance. Re-evaluating the distribution style (e.g., switching from AUTO or EVEN to KEY on a column with high cardinality and even distribution, or using ALL for small dimension tables) redistributes the data evenly, mitigating skew and improving parallel query execution.

Answer

Apply sort keys on the skewed columns.

Answer

Apply compression on the skewed columns.

Answer

Increase the number of nodes in the cluster.

Question 13

A company has an Amazon RDS for SQL Server DB instance with Multi-AZ deployment. During a recent failover test, the application experienced a longer downtime than expected. The application uses a single connection string. What change should be made to reduce failover downtime?

Accepted Answer

Use a custom DNS CNAME record pointing to the RDS endpoint.. Using a custom DNS CNAME record that points to the RDS endpoint allows the application to control the DNS Time-To-Live (TTL) value independently. By setting a low TTL (e.g., 5 seconds) on the CNAME, the application's DNS resolver will refresh the IP address more quickly after a failover, reducing the time the application spends trying to connect to the old, unreachable primary instance. This minimizes downtime because the application can resolve the new primary's IP address sooner, rather than relying on the default RDS endpoint's TTL, which is typically set to 60 seconds and cannot be modified.

Answer

Implement connection pooling in the application.

Answer

Set the DNS TTL to a higher value.

Answer

Configure the application to use the RDS instance ID instead of endpoint.

Question 14

A company is using Amazon DynamoDB and needs to export data to Amazon S3 for analysis. Which AWS service can perform this export without writing custom code?

Accepted Answer

AWS Glue. AWS Glue provides a built-in DynamoDB-to-S3 export feature that requires no custom code. You can create a Glue job using the 'Export DynamoDB table to S3' blueprint, which automatically handles schema inference, data conversion, and partitioning. This is the only option that directly supports the export without writing any code.

Answer

AWS Data Pipeline

Answer

Amazon EMR

Answer

DynamoDB Console

Question 15

Which THREE factors should be considered when planning a cross-Region disaster recovery strategy for an Amazon Aurora MySQL DB cluster? (Choose 3.)

Accepted Answer

Network latency between source and target Regions.. Network latency between source and target Regions directly impacts the replication lag for Amazon Aurora Global Database. Aurora uses asynchronous replication across Regions, and higher latency increases the delay between committing a transaction on the primary cluster and it being available on the secondary cluster, which affects the achievable Recovery Point Objective (RPO).

Answer

Provisioned IOPS for the primary cluster.

Answer

Failover priority of reader instances.