DEA-C01 Practice Test 22 — 15 Questions

Question 1

A company is designing a disaster recovery strategy for an Amazon RDS for SQL Server database. The database must be recoverable in another AWS region within 15 minutes of a regional outage. Which TWO actions should the data engineer take?

Accepted Answer

Configure automated cross-region snapshots to be copied to the recovery region.. Options A and D are correct. A cross-region read replica can be promoted to a standalone instance in another region, providing recovery within minutes. Automated cross-region snapshots can also be used to restore to another region. Option B is incorrect because Multi-AZ is within a region, not cross-region. Option C is incorrect because cross-region automated backups are not supported; you need snapshots.

Answer

Enable Multi-AZ deployment on the primary instance.

Answer

Configure automated backups to copy to the recovery region.

Question 2

A company uses Amazon Redshift for data warehousing. The data engineer notices that query performance has degraded over time. The tables are frequently updated with new data, and the data engineer suspects that the distribution style is causing data skew. Which distribution style should the data engineer use to minimize data skew?

Accepted Answer

EVEN distribution. Option A is correct because EVEN distribution distributes rows across slices evenly, minimizing skew when no good distribution key exists. Option B is wrong because KEY distribution can cause skew if the key is not unique. Option C is wrong because ALL distribution duplicates the table, which is not efficient for large tables. Option D is wrong because AUTO lets Redshift choose, but may not minimize skew if the key is poorly chosen.

Answer

KEY distribution on a column with high cardinality

Answer

AUTO distribution

Answer

ALL distribution

Question 3

A data engineer is reviewing the lifecycle configuration of an S3 bucket. The bucket stores log files. The engineer wants to ensure that objects are deleted after 365 days. What is the current behavior?

Accepted Answer

Objects are deleted after 365 days.. Option A is correct because the expiration rule deletes objects after 365 days. Option B is wrong because there is no transition to Glacier. Option C is wrong because objects transition to STANDARD_IA after 30 days, not immediately. Option D is wrong because noncurrent versions are not included.

Answer

Objects are transitioned to S3 Standard-IA immediately.

Answer

Objects are transitioned to S3 Glacier after 365 days.

Answer

Noncurrent versions of objects are deleted after 365 days.

Question 4

A company is using Amazon Redshift for analytics. The cluster has 20 nodes and the data is evenly distributed. Query performance has degraded over time. The data engineer suspects that table maintenance is needed. Which set of operations should be performed to improve query performance?

Accepted Answer

Run VACUUM and ANALYZE commands on all tables. Option A is correct because VACUUM reclaims space and sorts data, and ANALYZE updates statistics. Option B is wrong because VACUUM FULL is more intensive and not recommended unless necessary. Option C is wrong because REINDEX is for indexes, not sort order. Option D is wrong because ALTER TABLE APPEND does not help.

Answer

Run VACUUM FULL on all tables

Answer

Run REINDEX on all tables

Answer

Run ALTER TABLE APPEND to reorganize data

Question 5

A data engineer needs to migrate an on-premises Apache Hadoop cluster to AWS. The cluster stores data in HDFS and runs MapReduce jobs. The company wants to minimize operational overhead and leverage serverless technologies where possible. Which AWS service should the data engineer use to replace HDFS storage?

Accepted Answer

Amazon S3. Amazon S3 is the recommended storage layer for Hadoop workloads on AWS, providing durable, scalable object storage with no operational overhead. Option A is wrong because EMR is a compute service, not storage. Option B is wrong because EBS is block storage attached to EC2, not suitable as a standalone distributed storage for Hadoop. Option D is wrong because Redshift is a data warehouse, not a replacement for HDFS.

Answer

Amazon EBS

Answer

Amazon EMR

Answer

Amazon Redshift

Question 6

A data engineer needs to grant cross-account access to an S3 bucket. The engineer wants to use a role in the source account and assume that role from the target account. Which permissions are required?

Accepted Answer

Role in source account with trust policy allowing target account, and bucket policy granting access to the role. The target account needs sts:AssumeRole permission on the role ARN in the source account. The source account's bucket policy must also grant access to the assumed role. Option D is correct.

Answer

Bucket policy in source account allowing the target account's root user

Answer

Role in target account with trust policy allowing source account

Answer

IAM policy in target account allowing s3:GetObject on the bucket

Question 7

A company needs to store JSON documents that are accessed by a key-value pattern. The data is 500 GB and requires single-digit millisecond latency. Which AWS database is most suitable?

Accepted Answer

Amazon DynamoDB. Option C is correct because DynamoDB supports document store and key-value access with low latency. Option A is wrong because RDS is relational. Option B is wrong because Neptune is graph. Option D is wrong because Redshift is analytical.

Answer

Amazon Redshift

Answer

Amazon Neptune

Answer

Amazon RDS for MySQL

Question 8

A data engineer is designing a data lake on AWS using Amazon S3. The data consists of CSV files generated by IoT devices. The data is accessed by multiple analytics jobs, and the engineer needs to ensure that new files are immediately visible to all consumers after writing. What S3 consistency model applies?

Accepted Answer

Read-after-write consistency for new object PUTS.. Amazon S3 provides read-after-write consistency for PUTS of new objects (since 2020), meaning new objects are immediately readable. Option A is wrong because eventual consistency applies to overwrites and deletes. Option C is wrong because there is no strong consistency for all operations; S3 now provides strong consistency for all operations. Option D is wrong because no locking mechanism is needed for new objects.

Answer

Consistent reads require S3 Object Lock.

Answer

Strong consistency for all operations.

Answer

Eventual consistency for all operations.

Question 9

A company stores critical financial data in Amazon DynamoDB. To meet compliance requirements, the data must be encrypted at rest with a customer-managed key. Which solution should the data engineer implement?

Accepted Answer

Configure the DynamoDB table to use a customer managed key from AWS KMS.. Option C is correct because DynamoDB supports encryption at rest using AWS KMS customer managed keys. Option A is for S3. Option B is for RDS. Option D is not a DynamoDB feature.

Answer

Use AWS CloudHSM to generate a key and import it into DynamoDB.

Answer

Enable default encryption on the DynamoDB table using S3-managed keys.

Answer

Use AWS Certificate Manager to issue a certificate and configure TLS.

Question 10

Refer to the exhibit. A data engineer applies this bucket policy to an S3 bucket. A user within the 10.0.0.0/24 IP range attempts to upload an object to the bucket using an HTTP (non-HTTPS) request. What is the outcome?

Accepted Answer

The upload fails because the request is not using HTTPS.. Option B is correct because the Deny statement explicitly denies all s3 actions when SecureTransport is false, regardless of the Allow statement. The Explicit Deny overrides Allow. Option A is wrong because the Deny applies. Option C is wrong because the IP condition is only on Allow. Option D is wrong because the policy is valid.

Answer

The upload succeeds because the Allow statement grants permission.

Answer

The upload succeeds because the user's IP is allowed.

Answer

The upload fails because the user's IP is not in the allowed range for PutObject.

Question 11

A company uses Amazon DynamoDB with global tables in three AWS Regions. The data engineer needs to ensure that writes to the table in us-east-1 are replicated to other regions with minimal latency. Which DynamoDB feature should be used?

Accepted Answer

DynamoDB Global Tables. DynamoDB Global Tables provide multi-region replication with low latency. Option A is correct. Option B: DAX is a cache, not replication. Option C: TTL is for automatic item expiration. Option D: Streams capture changes but do not automatically replicate to other regions without custom code.

Answer

DynamoDB Time to Live (TTL)

Answer

DynamoDB Streams

Answer

DynamoDB Accelerator (DAX)

Question 12

A data pipeline using AWS Glue ETL jobs is failing intermittently with the error 'Rate exceeded' when writing to an Amazon Redshift cluster. Which action is MOST effective to resolve this issue?

Accepted Answer

Enable auto-tuning on the Redshift cluster and use concurrency scaling.. Option A is correct because enabling Redshift auto-tuning with concurrency scaling can automatically handle write spikes. Option B is wrong because increasing Glue job timeout does not address rate limiting. Option C is wrong because disabling Redshift WLM concurrency scaling would exacerbate the issue. Option D is wrong because using a different data format does not affect write rate limits.

Answer

Increase the timeout of the Glue ETL job to allow more time for retries.

Answer

Disable workload management (WLM) concurrency scaling in Redshift.

Answer

Change the output file format from Parquet to CSV to reduce write size.

Question 13

Which TWO actions can reduce the cost of an Amazon S3 bucket that stores infrequently accessed data? (Choose 2.)

Accepted Answer

Use lifecycle policies to expire objects after a certain period. Options A and C are correct because transitioning to S3 Standard-IA reduces cost for infrequent access, and lifecycle policies automatically transition objects. Option B is wrong because enabling versioning increases storage costs. Option D is wrong because MFA Delete does not affect storage cost. Option E is wrong because cross-region replication incurs additional costs.

Answer

Enable cross-region replication

Answer

Enable versioning to keep multiple versions

Answer

Enable MFA Delete for extra security

Question 14

A data engineer is designing a multi-region disaster recovery plan for an Amazon DynamoDB table. The table stores critical user profile data and must have a Recovery Point Objective (RPO) of less than 1 minute and a Recovery Time Objective (RTO) of less than 5 minutes. Which solution meets these requirements?

Accepted Answer

Use DynamoDB global tables to replicate data to another region.. DynamoDB global tables provide multi-region active-active replication with sub-second replication latency, meeting RPO < 1 minute and RTO < 5 minutes (by failing over to another region). Option A is wrong because on-demand backup and restore can take hours to restore. Option B is wrong because point-in-time recovery (PITR) restores to a new table, which can take minutes to hours. Option D is wrong because cross-region replication using Lambda is custom and may have higher latency.

Answer

Configure DynamoDB Streams and a Lambda function to replicate data to another region.

Answer

Use DynamoDB on-demand backup and restore to another region.

Answer

Enable point-in-time recovery (PITR) and restore to another region.

Question 15

A company uses Amazon Redshift for analytics. The data engineer notices that queries are slow and the system is experiencing high disk usage. The engineer suspects that the distribution style is suboptimal. Which action should the engineer take to improve query performance?

Accepted Answer

Use the DISTSTYLE AUTO setting and analyze query patterns to let Redshift choose.. Option B is correct because analyzing query patterns helps choose optimal distribution. Option A changes all tables, which may not be ideal. Option C is for storage, not distribution. Option D is for sort keys.

Answer

Convert all tables to use SORTKEY on the most frequently filtered column.

Answer

Increase the number of nodes in the cluster to distribute data across more slices.

Answer

Set all tables to DISTSTYLE EVEN to distribute data evenly.