Amazon Amazon Certifications DBS-C01 Questions & Answers

• Question 281:

  An ecommerce company uses Amazon DynamoDB as the backend for its payments system. A new regulation requires the company to log all data access requests for financial audits. For this purpose, the company plans to use AWS logging and save logs to Amazon S3.

  How can a database specialist activate logging on the database?

  A. Use AWS CloudTrail to monitor DynamoDB control-plane operations. Create a DynamoDB stream to monitor data-plane operations. Pass the stream to Amazon Kinesis Data Streams. Use that stream as a source for Amazon Kinesis Data Firehose to store the data in an Amazon S3 bucket.

  B. Use AWS CloudTrail to monitor DynamoDB data-plane operations. Create a DynamoDB stream to monitor control-plane operations. Pass the stream to Amazon Kinesis Data Streams. Use that stream as a source for Amazon Kinesis Data Firehose to store the data in an Amazon S3 bucket.

  C. Create two trails in AWS CloudTrail. Use Trail1 to monitor DynamoDB control-plane operations. Use Trail2 to monitor DynamoDB data-plane operations.

  D. Use AWS CloudTrail to monitor DynamoDB data-plane and control-plane operations.

  Correct Answer: D

  Explanation: https://aws.amazon.com/about-aws/whats-new/2021/04/you-now-can-use- aws-cloudtrail-to-log-amazon-dynamodb-streams-da/

• Question 282:

  A bike rental company operates an application to track its bikes. The application receives location and condition data from bike sensors. The application also receives rental transaction data from the associated mobile app.

  The application uses Amazon DynamoDB as its database layer. The company has configured DynamoDB with provisioned capacity set to 20% above the expected peak load of the application. On an average day, DynamoDB used 22 billion read capacity units (RCUs) and 60 billion write capacity units (WCUs). The application is running well. Usage changes smoothly over the course of the day and is generally shaped like a bell curve. The timing and magnitude of peaks vary based on the weather and season, but the general shape is consistent.

  Which solution will provide the MOST cost optimization of the DynamoDB database layer?

  A. Change the DynamoDB tables to use on-demand capacity.

  B. Use AWS Auto Scaling and configure time-based scaling.

  C. Enable DynamoDB capacity-based auto scaling.

  D. Enable DynamoDB Accelerator (DAX).

  Correct Answer: C

  https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/AutoScaling.html

• Question 283:

  A corporation wishes to move a 1 TB Oracle database from its current location to an Amazon Aurora PostgreSQL DB cluster. The database specialist at the firm noticed that the Oracle database stores 100 GB of large binary objects (LOBs) across many tables. The Oracle database supports LOBs up to 500 MB in size and an average of 350 MB. AWS DMS was picked by the Database Specialist to transfer the data with the most replication instances.

  How should the database specialist improve the transfer of the database to AWS DMS?

  A. Create a single task using full LOB mode with a LOB chunk size of 500 MB to migrate the data and LOBs together

  B. Create two tasks: task1 with LOB tables using full LOB mode with a LOB chunk size of 500 MB and task2 without LOBs

  C. Create two tasks: task1 with LOB tables using limited LOB mode with a maximum LOB size of 500 MB and task 2 without LOBs

  D. Create a single task using limited LOB mode with a maximum LOB size of 500 MB to migrate data and LOBs together

  Correct Answer: C

  https://docs.aws.amazon.com/dms/latest/userguide/CHAP_BestPractices.html#CHAP_Bes tPractices.LOBS,

  "AWS DMS migrates LOB data in two phases: 1. AWS DMS creates a new row in the target table and populates the row with all data except the associated LOB value. 2.AWS DMS updates the row in the target table with the LOB data." This

  means that we would need two tasks, one per phase and use limited LOB mode for best performance.

• Question 284:

  A company has a hybrid environment in which a VPC connects to an on-premises network through an AWS Site-to-Site VPN connection. The VPC contains an application that is hosted on Amazon EC2 instances. The EC2 instances run in

  private subnets behind an Application Load Balancer (ALB) that is associated with multiple public subnets. The EC2 instances need to securely access an Amazon DynamoDB table.

  Which solution will meet these requirements?

  A. Use the internet gateway of the VPC to access the DynamoDB table. Use the ALB to route the traffic to the EC2 instances.

  B. Add a NAT gateway in one of the public subnets of the VPC_ Configure the security groups of the EC2 instances to access the DynamoDB table through the NAT gateway

  C. Use the Site-to-Site VPN connection to route all DynamoD8 network traffic through the on-premises network infrastructure to access the EC2 instances

  D. Create a VPC endpoint for DynamoDB_ Assign the endpoint to the route table of the private subnets that contain the EC2 instances.

  Correct Answer: D

  Option D is correct because it meets the requirements of securely accessing a DynamoDB table from EC2 instances in a hybrid environment. A VPC endpoint for DynamoDB enables EC2 instances in a VPC to use their private IP addresses to access DynamoDB with no exposure to the public internet1. The EC2 instances do not require public IP addresses, and do not need an internet gateway, a NAT device, or a virtual private gateway in the VPC. The endpoint policy and the security groups of the EC2 instances can control access to DynamoDB. Traffic between the VPC and DynamoDB does not leave the Amazon network. Assigning the endpoint to the route table of the private subnets that contain the EC2 instances ensures that any requests to DynamoDB from those subnets are routed to the private endpoint within the Amazon network.

• Question 285:

  A web-based application uses Amazon DocumentDB (with MongoDB compatibility) as its underlying data store. Sufficient access control IS in place, but a database specialist wants to be able to review logs if the primary DocumentDB database is deleted.

  Which combination of steps Should the database specialist take to meet this requirement? (Select TWO_)

  A. Set the audit_logs cluster parameter to enabled

  B. Enable DocumentDB log export to Amazon CloudWatch Logs.

  C. Enable Enhanced Monitoring tor DocumentDB.

  D. Enable AWS CloudTrail for DocumentDB.

  E. use AWS Config to monitor the state of DocumentDB.

  Correct Answer: AB

  Option A is correct because it sets the audit_logs cluster parameter to enabled. This enables auditing on the DocumentDB cluster, which records events that were performed in the cluster, such as successful and failed authentication

  attempts, dropping a collection in a database, or creating an index1. By enabling auditing, the database specialist can review the logs to see who and when deleted the primary DocumentDB database, and what other actions were taken on

  the cluster.

  Option B is correct because it enables DocumentDB log export to Amazon CloudWatch Logs. This allows the DocumentDB cluster to export its auditing records (JSON documents) to Amazon CloudWatch Logs, where they can be analyzed,

  monitored, and archived1. By enabling log export, the database specialist can access the logs even if the primary DocumentDB database is deleted, as they are stored in a separate service.

• Question 286:

  A company is running a two-tier ecommerce application in one AWS account. The web server is deployed using an Amazon RDS for MySQL Multi-AZ DB instance. A Developer mistakenly deleted the database in the production environment. The database has been restored, but this resulted in hours of downtime and lost revenue.

  Which combination of changes in existing IAM policies should a Database Specialist make to prevent an error like this from happening in the future? (Choose three.)

  A. Grant least privilege to groups, users, and roles

  B. Allow all users to restore a database from a backup that will reduce the overall downtime to restore the database

  C. Enable multi-factor authentication for sensitive operations to access sensitive resources and API operations

  D. Use policy conditions to restrict access to selective IP addresses

  E. Use AccessList Controls policy type to restrict users for database instance deletion

  F. Enable AWS CloudTrail logging and Enhanced Monitoring

  Correct Answer: ACD

  https://aws.amazon.com/blogs/database/using-iam-multifactor-authentication-with-amazon- rds/ https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/security_iam_id-based- policy-html https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/DataDurability.html

• Question 287:

  A marketing company is developing an application to track responses to email message campaigns. The company needs a database storage solution that is optimized to work with highly connected data. The database needs to limit connections and programmatic access to the data by using IAM policies.

  Which solution will meet these requirements?

  A. Amazon ElastiCache for Redis cluster

  B. Amazon Aurora MySQL DB cluster

  C. Amazon DynamoDB table

  D. Amazon Neptune DB cluster

  Correct Answer: D

  Amazon Neptune is a fast, reliable, fully managed graph database service that makes it easy to build and run applications that work with highly connected data sets1. Graph databases are designed to store and query data that has complex

  relationships and interconnections, such as social networks, recommendation engines, fraud detection, and knowledge graphs2. Amazon Neptune supports two popular graph models: Property Graph and Resource Description Framework

  (RDF), and their respective query languages:

  Apache TinkerPop Gremlin and SPARQL2.

  Amazon Neptune also supports IAM policies to control access to the database resources and operations. You can use IAM database authentication to authenticate users and applications that connect to a Neptune DB cluster. IAM database

  authentication works with MySQL and PostgreSQL database clients. You can also use IAM roles to manage access to Neptune from other AWS services, such as Amazon EC2, AWS Lambda, and Amazon SageMaker2.

  Therefore, Amazon Neptune DB cluster is a suitable solution for the marketing company's requirements, as it can provide a graph database storage solution that is optimized for highly connected data and can limit connections and

  programmatic access by using IAM policies.

• Question 288:

  A company recently migrated its line-of-business (LOB) application to AWS. The application uses an Amazon RDS for SQL Server DB instance as its database engine.

  The company must set up cross-Region disaster recovery for the application. The company needs a solution with the lowest possible RPO and RTO.

  Which solution will meet these requirements?

  A. Create a cross-Region read replica of the DB instance. Promote the read replica at the time of failover.

  B. Set up SQL replication from the DB instance to an Amazon EC2 instance in the disaster recovery Region. Promote the EC2 instance as the primary server.

  C. Use AWS Database Migration Service (AWS KMS) for ongoing replication of the DB instance in the disaster recovery Region.

  D. Take manual snapshots of the DB instance in the primary Region. Copy the snapshots to the disaster recovery Region.

  Correct Answer: C

  Explanation: https://aws.amazon.com/blogs/database/cross-region-disaster-recovery-of- amazon-rds-for-sql-server/

• Question 289:

  A database specialist is responsible for an Amazon RDS for MySQL DB instance with one read replica. The DB instance and the read replica are assigned to the default parameter group. The database team currently runs test queries against a read replica. The database team wants to create additional tables in the read replica that will only be accessible from the read replica to benefit the tests.

  Which should the database specialist do to allow the database team to create the test tables?

  A. Contact AWS Support to disable read-only mode on the read replica. Reboot the read replica. Connect to the read replica and create the tables.

  B. Change the read_only parameter to false (read_only=0) in the default parameter group of the read replica. Perform a reboot without failover. Connect to the read replica and create the tables using the local_only MySQL option.

  C. Change the read_only parameter to false (read_only=0) in the default parameter group. Reboot the read replica. Connect to the read replica and create the tables.

  D. Create a new DB parameter group. Change the read_only parameter to false (read_only=0). Associate the read replica with the new group. Reboot the read replica. Connect to the read replica and create the tables.

  Correct Answer: D

  Explanation: https://aws.amazon.com/premiumsupport/knowledge-center/rds-read-replica/

• Question 290:

  An electric utility company wants to store power plant sensor data in an Amazon DynamoDB table. The utility company has over 100 power plants and each power plant has over 200 sensors that send data every 2 seconds. The sensor data includes time with milliseconds precision, a value, and a fault attribute if the sensor is malfunctioning. Power plants are identified by a globally unique identifier. Sensors are identified by a unique identifier within each power plant. A database specialist needs to design the table to support an efficient method of finding all faulty sensors within a given power plant.

  Which schema should the database specialist use when creating the DynamoDB table to achieve the fastest query time when looking for faulty sensors?

  A. Use the plant identifier as the partition key and the measurement time as the sort key. Create a global secondary index (GSI) with the plant identifier as the partition key and the fault attribute as the sort key.

  B. Create a composite of the plant identifier and sensor identifier as the partition key. Use the measurement time as the sort key. Create a local secondary index (LSI) on the fault attribute.

  C. Create a composite of the plant identifier and sensor identifier as the partition key. Use the measurement time as the sort key. Create a global secondary index (GSI) with the plant identifier as the partition key and the fault attribute as the sort key.

  D. Use the plant identifier as the partition key and the sensor identifier as the sort key. Create a local secondary index (LSI) on the fault attribute.

  Correct Answer: D

  Explanation: Plant id as partition key and Sensor id as a sort key. Fault can be identified quickly using the local secondary index and associated plant and sensor can be identified easily.