DBS-C01 Management and Operations Practice Test 13 — 15 Questions

Question 1

Which THREE factors should be considered when selecting the backup strategy for an Amazon RDS for PostgreSQL DB instance? (Choose 3.)

Accepted Answer

The backup retention period. The backup retention period directly determines how far back you can perform a point-in-time recovery (PITR) for an RDS for PostgreSQL instance. Amazon RDS stores automated backups and transaction logs for the specified retention period (1 to 35 days), and this period must be aligned with your compliance and operational requirements. Choosing an appropriate retention period is a fundamental factor in defining the backup strategy.

Answer

The need for Multi-AZ deployment

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The encryption at rest requirement

Question 2

Which TWO methods can be used to reduce the read latency for an Amazon Aurora MySQL database? (Choose 2.)

Accepted Answer

Use Aurora Auto Scaling to add replica capacity based on load. Aurora Auto Scaling automatically adjusts the number of Aurora Replicas in response to changes in read workload, thereby reducing read latency by distributing read traffic across additional replicas. Option E is correct because adding Aurora Replicas offloads read queries from the primary instance, allowing parallel processing of read requests and reducing contention, which directly lowers read latency.

Answer

Enable encryption at rest

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Increase the write capacity of the DB instance

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Enable Amazon ElastiCache in front of the database

Question 3

A company is experiencing increased latency on their Amazon RDS for PostgreSQL instance. The application team reports that queries are taking longer than usual. The database metrics show high CPU utilization and a spike in write operations. Which initial step should the database specialist take to diagnose the issue?

Accepted Answer

Enable Performance Insights on the DB instance to analyze the workload.. Enabling Performance Insights provides a detailed performance analysis and helps identify the root cause of the latency. It is the recommended first step for diagnosing database performance issues.

Answer

Create a read replica to offload read traffic from the primary instance.

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Modify the DB instance to a larger instance class to handle the load.

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Enable enhanced monitoring to get OS-level metrics of the DB instance.

Question 4

A database administrator needs to automate the backup process for an Amazon RDS for MySQL DB instance. The backups must be retained for 30 days and should be taken daily. Which AWS service should be used to implement this automation?

Accepted Answer

Amazon RDS automated backups. Amazon RDS automated backups are the native, built-in mechanism for backing up RDS DB instances. They automatically take daily snapshots during the backup window and retain transaction logs for point-in-time recovery. By default, the retention period can be set from 1 to 35 days, so configuring it to 30 days meets the requirement without any additional services or custom scripting.

Answer

Amazon S3 lifecycle policies

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AWS Backup

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AWS Lambda with custom scripts

Question 5

A company is running an Amazon DynamoDB table with on-demand capacity mode. The table experiences occasional throttling during peak hours. The application team wants to understand the read/write patterns to optimize the table design. Which approach should the database specialist take to analyze the throttling events?

Accepted Answer

Enable CloudWatch Contributor Insights for DynamoDB to identify throttled requests.. CloudWatch Contributor Insights analyzes high-cardinality attributes and provides detailed information about throttling requests, such as which items or partitions are causing throttling.

Answer

Enable DynamoDB Accelerator (DAX) to cache reads and reduce throttling.

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Use AWS CloudTrail to log all DynamoDB API calls and analyze the logs.

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Switch to provisioned capacity mode with auto scaling to handle the spikes.

Question 6

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database size is 500 GB. The migration must have minimal downtime. Which AWS service should be used to perform the migration?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is the correct choice because it supports heterogeneous migrations from Oracle to Amazon RDS for Oracle with minimal downtime. DMS can perform continuous replication using Oracle's change data capture (CDC) via LogMiner or binary reader, allowing the source database to remain operational during the migration. This makes it ideal for a 500 GB database where downtime must be minimized.

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AWS Snowball Edge

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AWS DataSync

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Amazon RDS for Oracle snapshot copy

Question 7

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

Accepted Answer

DatabaseConnections. The DatabaseConnections metric in CloudWatch shows the number of current connections to the DB instance.

Answer

NetworkThroughput

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ConnectionAttempts

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ActiveTransactions

Question 8

A company uses Amazon Aurora MySQL-Compatible Edition. The database specialist notices that the DB cluster's failover time is longer than expected. The primary instance is using a db.r5.large instance class. Which change would most likely reduce the failover time?

Accepted Answer

Use a larger instance class for the Aurora Replicas.. Using a larger instance class for Aurora replicas ensures they can handle the workload after failover, potentially reducing failover time. However, the key factor is that Aurora failover is typically fast, but if replicas are undersized, the time to promote and become fully operational increases. Using a larger instance class for the replicas (or all instances) can help.

Answer

Enable Backtrack on the DB cluster.

Answer

Increase the number of Aurora Replicas.

Answer

Enable Multi-AZ deployment for the DB cluster.

Question 9

A company is using Amazon Redshift for data warehousing. The database administrator needs to identify which queries are consuming the most resources. Which system view should be queried?

Accepted Answer

STV_RECENTS. The STV_RECENTS system view in Amazon Redshift provides a list of currently running and recently completed queries, including their process IDs, user names, and execution status. This makes it the correct choice for identifying which queries are consuming the most resources at the moment, as it directly reflects active and recent workload.

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SVV_TABLES

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STL_LOAD_ERRORS

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STL_DDLTEXT

Question 10

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

Accepted Answer

AWS CloudTrail. AWS CloudTrail is the correct service because it records API activity for Amazon RDS, including calls to create, modify, or delete DB instances, as well as changes to security groups, parameter groups, and automated backups. CloudTrail logs these events to an S3 bucket or CloudWatch Logs, providing a durable audit trail for all management-plane operations on the RDS DB instance. This directly meets the requirement to log all changes for auditing purposes.

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AWS Config

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Amazon GuardDuty

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Amazon Inspector

Question 11

A database administrator sees the above error logs in CloudWatch for an Amazon RDS for PostgreSQL DB instance. The application team confirms that the password for 'app_user' is correct. What is the most likely cause of the authentication failures?

Accepted Answer

The host '10.0.1.50' is not listed in the pg_hba.conf file.. The errors show authentication failures from a specific host. If the password is correct, the most likely cause is that the host is not allowed by the pg_hba.conf configuration. RDS for PostgreSQL uses DB parameter groups to control pg_hba.conf rules; the rds.force_ssl parameter or the pg_hba.conf entries may not include that host.

Answer

The password has expired for 'app_user'.

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The user 'app_user' does not have the LOGIN privilege.

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The database is in read-only mode.

Question 12

Which TWO of the following are valid strategies for reducing costs for an Amazon DynamoDB table with on-demand capacity mode? (Choose TWO.)

Accepted Answer

Implement DynamoDB Accelerator (DAX) to cache reads.. Implementing DAX reduces the number of read requests to the underlying DynamoDB table by serving cached results, which lowers read capacity consumption and thus reduces costs for on-demand tables. Switching to provisioned capacity with auto scaling allows you to pay for a baseline of read/write capacity units rather than per-request pricing, which is more cost-effective for predictable or steady workloads.

Answer

Use Amazon DynamoDB TTL to automatically delete expired data.

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Enable DynamoDB global tables to distribute traffic.

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Use DynamoDB Streams to process updates asynchronously.

Question 13

Which THREE of the following are required to set up cross-Region replication for an Amazon RDS for MySQL DB instance? (Choose THREE.)

Accepted Answer

The source DB instance must be in a VPC.. For cross-Region replication of an Amazon RDS for MySQL DB instance, the source DB instance must have automated backups enabled (option D). This is typically achieved by setting a backup retention period of at least 1 day (option A is not a separate requirement; it is the mechanism to enable automated backups). The source DB instance must be in a VPC (option B), and a read replica must be created in the target Region (option C). Multi-AZ deployment (option E) is not required.

Answer

The backup retention period on the source must be at least 1 day.

Answer

The source DB instance must be a Multi-AZ deployment.

Question 14

Which TWO of the following are benefits of using Amazon RDS Proxy? (Choose TWO.)

Accepted Answer

Reduces the number of database connections by pooling them.. Amazon RDS Proxy acts as a connection broker between your application and the database, maintaining a pool of established connections. When the application opens a new connection, RDS Proxy reuses an idle connection from the pool, which reduces the total number of database connections and prevents the database from being overwhelmed. This pooling mechanism directly addresses the issue of connection exhaustion, especially in serverless or highly concurrent environments.

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Automatically encrypts all traffic between the application and the database.

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Provides built-in read/write splitting for read replicas.

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Reduces storage costs by compressing data in transit.

Question 15

A database administrator is creating an IAM policy to allow a DevOps engineer to manage production RDS instances. The policy above is attached to the engineer's IAM role. The engineer reports that they cannot create a new DB instance with the identifier 'prod-analytics'. What is the most likely reason?

Accepted Answer

The engineer does not have permissions to pass an IAM role to the DB instance if one is specified.. The most likely reason is that when creating the DB instance, the engineer specified an IAM role to be associated with the instance (e.g., for backup or monitoring). The attached policy does not include an 'iam:PassRole' action, which is required to pass the role to RDS. Without it, the CreateDBInstance call fails due to insufficient permissions to pass the specified role.

Answer

The policy does not allow the 'rds:CreateDBInstance' action on the required resource because the resource ARN pattern is incorrect.

Answer

The policy does not include the 'rds:CreateDBSecurityGroup' action.

Answer

The policy does not include the 'rds:CreateDBInstance' action for all regions.