DBS-C01 Practice Test 10 — 10 Questions

Question 1

A company is migrating an on-premises MongoDB database to AWS. They need a managed database service that is compatible with MongoDB and supports automated backups, scaling, and high availability. Which service should they use?

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

Accepted Answer

Amazon DocumentDB. Amazon DocumentDB is a fully managed, MongoDB-compatible document database service designed for workloads that require MongoDB's document model, query patterns, and APIs. It supports automated backups (continuous backups to S3 with point-in-time recovery), automatic scaling of storage and compute, and multi-AZ high availability with synchronous replication across three Availability Zones, making it the correct choice for migrating an on-premises MongoDB database to a managed AWS service.

Answer

Amazon DynamoDB

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Amazon RDS for MySQL

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Amazon Neptune

Question 2

A company wants to migrate an on-premises SQL Server database to Amazon RDS for SQL Server. They need to convert stored procedures and functions. Which AWS service should they use?

Accepted Answer

AWS SCT. AWS SCT (Schema Conversion Tool) is the correct service because it specializes in converting database schemas, including stored procedures and functions, from one engine to another. For migrating on-premises SQL Server to Amazon RDS for SQL Server, SCT can analyze and convert the schema objects, handling syntax differences and compatibility issues automatically.

Answer

AWS CloudEndure Migration

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AWS DMS

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AWS Snowball

Question 3

A company needs to store and query time-series data from IoT sensors. The data is written continuously and queried by time range for dashboards. Which AWS database service is most cost-effective and scalable for this workload?

Accepted Answer

Amazon Timestream.. Amazon Timestream is purpose-built for time-series data, offering automatic tiering between in-memory and magnetic stores for cost efficiency, and built-in functions for time-based aggregations and windowed queries. It is serverless and scales automatically to handle continuous writes from IoT sensors and low-latency dashboard queries by time range, making it the most cost-effective and scalable choice.

Answer

Amazon ElastiCache for Redis with time-series data structures.

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Amazon DynamoDB with time-based partition keys.

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Amazon RDS for PostgreSQL with time-based indexing.

Question 4

A security auditor reviews the output of a DynamoDB table description command as shown in the exhibit. Which statement accurately describes the encryption configuration of the Users table?

Accepted Answer

The table is encrypted using a customer managed KMS key.. The output shows SSEDescription with Status ENABLED, SSEType KMS, and a KMSMasterKeyArn, which indicates that the table is encrypted using a customer-managed KMS key. Option A is incorrect because AWS managed KMS keys do not have an ARN like the one shown; they would have an alias like 'aws/dynamodb'. Option B is incorrect because DynamoDB does not use S3 managed keys; the SSEType is KMS. Option C is incorrect because the status is ENABLED, indicating encryption at rest is enabled.

Answer

The table is encrypted using an AWS managed KMS key.

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The table uses server-side encryption with an S3 managed key.

Answer

The table is not encrypted at rest.

Question 5

Which TWO of the following are valid methods to migrate an on-premises MySQL database to Amazon RDS for MySQL? (Select TWO.)

Accepted Answer

Use AWS DMS to migrate from on-premises MySQL to RDS.. AWS DMS (Database Migration Service) is a fully managed service designed to migrate databases to AWS with minimal downtime. It supports homogeneous migrations like MySQL to Amazon RDS for MySQL, handling schema conversion, data replication, and ongoing changes via change data capture (CDC). This makes option B a valid and recommended method for migrating an on-premises MySQL database to RDS.

Answer

Use pg_dump to export the data and import into RDS.

Answer

Use SQL Server Integration Services (SSIS) to migrate the data.

Answer

Use Oracle Data Pump to export the data and import into RDS.

Question 6

A company is using Amazon ElastiCache for Redis as a caching layer in front of an Amazon Aurora MySQL database. The application is experiencing higher latency than expected. Which database design pattern should the specialist recommend to improve read performance?

Accepted Answer

Use Aurora Replicas to offload read traffic from the primary instance.. The application is experiencing higher latency than expected despite using ElastiCache for Redis. This indicates that the cache is not effectively absorbing read traffic, likely due to cache misses or insufficient cache hit ratio. By using Aurora Replicas, read traffic can be offloaded from the primary Aurora instance, reducing load and improving read performance directly at the database layer, which complements the caching layer.

Answer

Increase the ElastiCache cluster size to accommodate more data.

Answer

Enable Multi-AZ on the ElastiCache cluster and use read replicas.

Answer

Implement Amazon DynamoDB Accelerator (DAX) in front of Aurora.

Question 7

A company is deploying an Amazon Aurora MySQL database with read replicas. They need to ensure high availability and disaster recovery across AWS Regions. Which THREE components should be included?

Accepted Answer

Aurora Replicas in the same Region. Aurora Replicas in the same Region provide read scaling and automatic failover within an AWS Region. They share the same underlying storage volume as the primary instance, so failover is fast (typically under 30 seconds) and does not require data rehydration. This is a core component for high availability within a single Region.

Answer

Auto Scaling groups

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Amazon CloudFront

Question 8

A gaming company runs a leaderboard application on Amazon DynamoDB. The application experiences sudden spikes in read traffic during tournaments. The table uses on-demand capacity and the reads are eventually consistent. However, some users report stale data for several seconds. What is the most likely cause?

Accepted Answer

The application is using eventually consistent reads.. Eventually consistent reads in DynamoDB can return stale data for up to one second under normal conditions, but during sudden spikes in read traffic, the replication lag can extend to several seconds. The application is using eventually consistent reads, which trade immediate consistency for higher throughput and lower latency, making stale data more likely during high-traffic periods like tournaments.

Answer

The table is using on-demand capacity instead of provisioned capacity.

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The table has a global secondary index (GSI) that is not updated synchronously.

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The read capacity units are insufficient for the traffic spikes.

Question 9

A company is migrating an on-premises Oracle database to Amazon RDS for Oracle. The database uses Oracle Data Guard for disaster recovery. Which AWS service should be used to monitor the replication lag between the source and target databases during migration?

Accepted Answer

AWS Database Migration Service (AWS DMS). AWS DMS provides metrics for replication lag. Option A is wrong because Performance Insights does not monitor replication lag. Option C is wrong because CloudWatch can monitor DMS metrics but is not specific to Data Guard. Option D is wrong because CloudTrail does not monitor replication lag.

Answer

Amazon RDS Performance Insights

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Amazon CloudWatch

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AWS CloudTrail

Question 10

An administrator needs to migrate an on-premises MongoDB database to Amazon DocumentDB. The migration must have near-zero downtime. Which approach should the administrator use?

Accepted Answer

Use AWS DMS with MongoDB as source and DocumentDB as target. AWS DMS supports ongoing replication (change data capture) from MongoDB to Amazon DocumentDB, enabling near-zero downtime migrations by keeping the target synchronized with the source until cutover. This approach avoids the downtime required by offline methods like mongodump/mongorestore or bulk data transfer tools.

Answer

Use AWS DataSync to transfer the MongoDB data files

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Use AWS Glue to extract and load data

Answer

Use mongodump to export and mongorestore to import