Amazon Amazon Certifications DBS-C01 Questions & Answers

• Question 181:

  An online gaming company is using an Amazon DynamoDB table in on-demand mode to store game scores. After an intensive advertisement campaign in South

  America, the average number of concurrent users rapidly increases from 100,000 to 500,000 in less than 10 minutes every day around 5 PM.

  The on-call software reliability engineer has observed that the application logs contain a high number of DynamoDB throttling exceptions caused by game score insertions around 5 PM. Customer service has also reported that several users are complaining about their scores not being registered.

  How should the database administrator remediate this issue at the lowest cost?

  A. Enable auto scaling and set the target usage rate to 90%.

  B. Switch the table to provisioned mode and enable auto scaling.

  C. Switch the table to provisioned mode and set the throughput to the peak value.

  D. Create a DynamoDB Accelerator cluster and use it to access the DynamoDB table.

  Correct Answer: B

• Question 182:

  A Database Specialist is migrating a 2 TB Amazon RDS for Oracle DB instance to an RDS for PostgreSQL DB instance using AWS DMS. The source RDS Oracle DB instance is in a VPC in the us-east-1 Region. The target RDS for PostgreSQL DB instance is in a VPC in the use-west-2 Region.

  Where should the AWS DMS replication instance be placed for the MOST optimal performance?

  A. In the same Region and VPC of the source DB instance

  B. In the same Region and VPC as the target DB instance

  C. In the same VPC and Availability Zone as the target DB instance

  D. In the same VPC and Availability Zone as the source DB instance

  Correct Answer: C

  https://docs.aws.amazon.com/dms/latest/userguide/CHAP_ReplicationInstance.VPC.html # CHAP_ReplicationInstance.VPC.Configurations.ScenarioVPCPeer In fact, all the configurations list on above url prefer the replication instance putting into target vpc region / subnet / az. https://docs.aws.amazon.com/dms/latest/sbs/CHAP_SQLServer2Aurora.Steps.CreateRepli cationInstance.html

• Question 183:

  A database professional is tasked with the task of migrating 25 GB of data files from an on- premises storage system to an Amazon Neptune database.

  Which method of data loading is the FASTEST?

  A. Upload the data to Amazon S3 and use the Loader command to load the data from Amazon S3 into the Neptune database.

  B. Write a utility to read the data from the on-premises storage and run INSERT statements in a loop to load the data into the Neptune database.

  C. Use the AWS CLI to load the data directly from the on-premises storage into the Neptune database.

  D. Use AWS DataSync to load the data directly from the on-premises storage into the Neptune database.

  Correct Answer: A

  1.Copy the data files to an Amazon Simple Storage Service (Amazon S3) bucket.

  2.

  Create an IAM role with Read and List access to the bucket.

  3.

  Create an Amazon S3 VPC endpoint.

  4.

  Start the Neptune loader by sending a request via HTTP to the Neptune DB instance.

  5.

  The Neptune DB instance assumes the IAM role to load the data from the bucket.

• Question 184:

  A company is launching a new Amazon RDS for MySQL Multi-AZ DB instance to be used as a data store for a custom-built application. After a series of tests with point-in-time recovery disabled, the company decides that it must have point-in-time recovery reenabled before using the DB instance to store production data.

  What should a database specialist do so that point-in-time recovery can be successful?

  A. Enable binary logging in the DB parameter group used by the DB instance.

  B. Modify the DB instance and enable audit logs to be pushed to Amazon CloudWatch Logs.

  C. Modify the DB instance and configure a backup retention period

  D. Set up a scheduled job to create manual DB instance snapshots.

  Correct Answer: C

  Explanation: You can restore a DB instance to a specific point in time (PITR), creating a new DB instance. To support PITR, your DB instances must have backup retention set to a nonzero value. https://docs.aws.amazon.com/AmazonRDS/

  latest/UserGuide/custom- backup-sqlserver.html

  https://aws.amazon.com/blogs/database/setting-up-a-binlog-server-for-amazon-rds-mysql- and-mariadb-using-mariadb-maxscale/

  "After you run the command, it's okay to enable backup retention on the RDS instance by using the AWS CLI or the console. Enabling backup retention also enables binary logging." https://aws.amazon.com/blogs/storage/point-in-timerecovery-and-continuous-backup-for- amazon-rds-with-aws-backup/

• Question 185:

  Recently, a gaming firm purchased a popular iOS game that is especially popular during the Christmas season. The business has opted to include a leaderboard into the game, which will be powered by Amazon DynamoDB. The application's load is likely to increase significantly throughout the Christmas season.

  Which solution satisfies these criteria at the lowest possible cost?

  A. DynamoDB Streams

  B. DynamoDB with DynamoDB Accelerator

  C. DynamoDB with on-demand capacity mode

  D. DynamoDB with provisioned capacity mode with Auto Scaling

  Correct Answer: D

  Explanation: "On-demand is ideal for bursty, new, or unpredictable workloads whose traffic can spike in seconds or minutes"

  vs.

  'DynamoDB released auto scaling to make it easier for you to manage capacity efficiently, and auto scaling continues to help DynamoDB users lower the cost of workloads that have a predictable traffic pattern."

  https://aws.amazon.com/blogs/database/amazon-dynamodb-auto-scaling-performance- and-cost-optimization-at-any-scale/

• Question 186:

  A company is going through a security audit. The audit team has identified cleartext master user password in the AWS CloudFormation templates for Amazon RDS for MySQL DB instances. The audit team has flagged this as a security risk to the database team.

  What should a database specialist do to mitigate this risk?

  A. Change all the databases to use AWS IAM for authentication and remove all the cleartext passwords in CloudFormation templates.

  B. Use an AWS Secrets Manager resource to generate a random password and reference the secret in the CloudFormation template.

  C. Remove the passwords from the CloudFormation templates so Amazon RDS prompts for the password when the database is being created.

  D. Remove the passwords from the CloudFormation template and store them in a separate file. Replace the passwords by running CloudFormation using a sed command.

  Correct Answer: B

  Explanation: https://aws.amazon.com/blogs/infrastructure-and-automation/securing- passwords-in-aws-quick-starts-using-aws-secrets-manager/

• Question 187:

  A global company is creating an application. The application must be highly available. The company requires an RTO and an RPO of less than 5 minutes. The company needs a database that will provide the ability to set up an active-active configuration and near real- time synchronization of data across tables in multiple AWS Regions.

  Which solution will meet these requirements?

  A. Amazon RDS for MariaDB with cross-Region read replicas

  B. Amazon RDS With a Multi-AZ deployment

  C. Amazon DynamoDB global tables

  D. Amazon DynamoDB With a global secondary index (GSI)

  Correct Answer: C

  Amazon DynamoDB global tables are a fully managed, serverless, multi-Region, and multi- active database option that delivers fast and localized read and write performance for massively scaled global applications. Global tables provide you

  99.999% availability, increased application resiliency, and improved business continuity1. As global tables replicate your Amazon DynamoDB tables automatically across your choice of AWS Regions, you can achieve fast, local read and write

  performance1. In the rare event of a single Region failure, there is no need for a database failover as global tables' multi-active architecture allows customers to read and write to any replica table1. Global tables also eliminate the difficult work

  of replicating data between Regions and resolving update conflicts for multi-active workloads1.

  Using Amazon DynamoDB global tables, the company can:

  Set up an active-active configuration and near real-time synchronization of data across tables in multiple AWS Regions.

  Meet the RTO and RPO of less than 5 minutes, as global tables provide automatic failover and zero data loss in case of a Region failure. Achieve high availability, durability, and scalability for their application.

• Question 188:

  A database specialist is working on an Amazon RDS for PostgreSQL DB instance that is experiencing application performance issues due to the addition of new workloads. The database has 5 ? of storage space with Provisioned IOPS. Amazon CloudWatch metrics show that the average disk queue depth is greater than 200 and that the disk I/O response time is significantly higher than usual.

  What should the database specialist do to improve the performance of the application immediately?

  A. Increase the Provisioned IOPS rate on the storage.

  B. Increase the available storage space.

  C. Use General Purpose SSD (gp2) storage with burst credits.

  D. Create a read replica to offload Read IOPS from the DB instance.

  Correct Answer: A

• Question 189:

  A Database Specialist is setting up a new Amazon Aurora DB cluster with one primary instance and three Aurora Replicas for a highly intensive, business-critical application. The Aurora DB cluster has one medium- sized primary instance, one large-sized replica, and two medium sized replicas. The Database Specialist did not assign a promotion tier to the replicas.

  In the event of a primary failure, what will occur?

  A. Aurora will promote an Aurora Replica that is of the same size as the primary instance

  B. Aurora will promote an arbitrary Aurora Replica

  C. Aurora will promote the largest-sized Aurora Replica

  D. Aurora will not promote an Aurora Replica

  Correct Answer: C

  Priority: If you don't select a value, the default is tier-1. This priority determines the order in which Aurora https://docs.amazonaws.cn/en_us/AmazonRDS/latest/AuroraUserGuide/aurora-replicas- adding.html

  More than one Aurora Replica can share the same priority, resulting in promotion tiers. If two or more Aurora Replicas share the same priority, then Amazon RDS promotes the replica that is largest in size. If two or more Aurora Replicas share the same priority and size, then Amazon RDS promotes an arbitrary replica in the same promotion tier. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Managing.Back ups.html#Aurora.Managing.FaultTolerance

  If two or more Aurora Replicas share the same priority, then Amazon RDS promotes the replica that is largest in size. If two or more Aurora Replicas share the same priority and size, then Amazon RDS promotes an arbitrary replica in the same promotion tier. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Concepts.AuroraHigh Availability.html

• Question 190:

  A retail company manages a web application that stores data in an Amazon DynamoDB table. The company is undergoing account consolidation efforts. A database engineer needs to migrate the DynamoDB table from the current AWS account to a new AWS account.

  Which strategy meets these requirements with the LEAST amount of administrative work?

  A. Use AWS Glue to crawl the data in the DynamoDB table. Create a job using an available blueprint to export the data to Amazon S3. Import the data from the S3 file to a DynamoDB table in the new account.

  B. Create an AWS Lambda function to scan the items of the DynamoDB table in the current account and write to a file in Amazon S3. Create another Lambda function to read the S3 file and restore the items of a DynamoDB table in the new account.

  C. Use AWS Data Pipeline in the current account to export the data from the DynamoDB table to a file in Amazon S3. Use Data Pipeline to import the data from the S3 file to a DynamoDB table in the new account.

  D. Configure Amazon DynamoDB Streams for the DynamoDB table in the current account. Create an AWS Lambda function to read from the stream and write to a file in Amazon S3. Create another Lambda function to read the S3 file and restore the items to a DynamoDB table in the new account.

  Correct Answer: C

  https://aws.amazon.com/premiumsupport/knowledge-center/dynamodb-cross-account- migration/ https://aws.amazon.com/premiumsupport/knowledge-center/data-pipeline-account-access- dynamodb-s3/