DEA-C01 Practice Test 16 — 15 Questions

Question 1

A company is using Amazon S3 to store sensitive data. To meet compliance requirements, they need to automatically transition objects to S3 Glacier Deep Archive after 90 days and delete them after 7 years. What is the MOST cost-effective way to configure this?

Accepted Answer

Configure an S3 Lifecycle policy to transition objects to Glacier Deep Archive after 90 days and expire them after 7 years.. Option C is correct because a lifecycle policy can transition objects based on age and delete them after a specified period. Option A is wrong because manual deletion is error-prone and not automated. Option B is wrong because S3 Intelligent-Tiering does not delete objects. Option D is wrong because S3 Object Lock is for retention, not lifecycle management.

Answer

Manually move objects to Glacier Deep Archive and delete them using a script.

Answer

Use S3 Intelligent-Tiering to automatically move objects to Glacier Deep Archive and set expiration.

Answer

Enable S3 Object Lock with a retention period of 7 years and use a lifecycle policy to transition to Glacier Deep Archive.

Question 2

A company is designing a multi-Region disaster recovery solution for Amazon DynamoDB. They need to ensure that data is replicated across Regions with minimal latency and that applications can read from any Region. Which THREE steps should be taken? (Choose THREE.)

Accepted Answer

Configure application to read from any Region using the DynamoDB endpoint.. Options A, C, and E are correct. Global Tables replicate data across Regions. DynamoDB Streams capture changes for replication. Applications can read from any Region. Option B is wrong because DAX is not required for global replication. Option D is wrong because TTL is for expiration, not replication.

Answer

Configure Time to Live (TTL) to automatically expire old data.

Answer

Deploy DynamoDB Accelerator (DAX) in each Region.

Question 3

A data engineer needs to store semi-structured JSON data that is accessed infrequently but requires millisecond retrieval latency. The data is immutable once written. Which AWS service is most cost-effective?

Accepted Answer

Amazon S3 (Standard-IA) with S3 Select. Option A is correct because S3 with S3 Select can retrieve specific JSON fields with low latency for infrequent access, and Standard-IA reduces cost. Option B (DynamoDB) is for frequent access patterns. Option C (RDS) is for relational data. Option D (ElastiCache) is for caching, not durable storage.

Answer

Amazon DynamoDB with on-demand capacity

Answer

Amazon ElastiCache for Redis

Answer

Amazon RDS for PostgreSQL with JSONB

Question 4

A company uses Amazon S3 to store sensitive data. The security team wants to ensure that all objects uploaded to a specific S3 bucket are automatically encrypted at rest using server-side encryption with AWS KMS managed keys (SSE-KMS). Which bucket policy statement should be added to enforce this requirement?

Accepted Answer

Deny put requests where 's3:x-amz-server-side-encryption' is not 'aws:kms'. Option C is correct because the condition 's3:x-amz-server-side-encryption': 'aws:kms' enforces SSE-KMS. Option A denies requests with SSE-S3 but allows unencrypted uploads. Option B denies without encryption but allows SSE-S3. Option D denies SSE-KMS, which is the opposite of what is needed.

Answer

Deny put requests where 's3:x-amz-server-side-encryption' is 'aws:kms'

Answer

Deny put requests where 's3:x-amz-server-side-encryption' is not 'AES256'

Answer

Deny put requests where 's3:x-amz-server-side-encryption' is not set

Question 5

Which THREE factors should a data engineer consider when choosing between Amazon S3 and Amazon DynamoDB for storing time-series data? (Choose three.)

Accepted Answer

Required query complexity (simple key lookups vs. range scans). Options B, C, and D are correct because data access patterns, query complexity, and latency requirements are key factors. Option A (cost) is a consideration but not specific to time-series. Option E (data volume) is less relevant as both scale.

Answer

Cost per GB of storage

Answer

Total data volume

Question 6

A company wants to enforce that all data in an S3 bucket is encrypted at rest using AWS KMS. Which bucket policy condition key should be used?

Accepted Answer

s3:x-amz-server-side-encryption with value aws:kms. Condition key 's3:x-amz-server-side-encryption' with value 'aws:kms' enforces KMS encryption. 's3:x-amz-server-side-encryption-aws-kms-key-id' is for specific key ID.

Answer

s3:x-amz-acl with value bucket-owner-full-control

Answer

s3:x-amz-server-side-encryption with value AES256

Answer

aws:SourceIp with value 10.0.0.0/8

Question 7

A data engineer is monitoring a Redshift cluster that is experiencing slow query performance. The cluster has 4 dc2.large nodes. The engineer notices that disk space usage is at 85% across all nodes. Which action would MOST likely improve query performance?

Accepted Answer

Increase the number of nodes to 8.. Option D is correct because adding more nodes distributes data and improves I/O parallelism. Option A is wrong because vacuum reclaims space but does not help if disk usage is high due to data volume. Option B is wrong because DISTKEY and SORTKEY changes are design-time decisions. Option C is wrong because compression is already applied at load time.

Answer

Change the table design to use DISTKEY and SORTKEY.

Answer

Enable compression on all columns.

Answer

Run the VACUUM command to reclaim space.

Question 8

A data engineer needs to store JSON documents that are frequently updated and require ACID transactions. Which AWS database service is most appropriate?

Accepted Answer

Amazon DynamoDB. Option A is correct because Amazon DynamoDB supports JSON documents and ACID transactions via DynamoDB Transactions. Option B is wrong because Amazon S3 is not a database and does not support transactions. Option C is wrong because Amazon DocumentDB is a MongoDB-compatible database but ACID transactions are limited. Option D is wrong because Amazon Neptune is a graph database, not optimized for JSON documents.

Answer

Amazon Neptune

Answer

Amazon DocumentDB

Answer

Amazon S3

Question 9

A data engineer needs to store JSON documents that are frequently read and written by a web application. The data has a flexible schema and requires low-latency queries on primary key lookups. Which AWS service is MOST suitable?

Accepted Answer

Amazon DynamoDB. Option B is correct because DynamoDB is a NoSQL database designed for low-latency key-value lookups with flexible schema. Option A is wrong because RDS is relational and requires fixed schema. Option C is wrong because S3 is object storage, not designed for low-latency primary key lookups. Option D is wrong because Redshift is a data warehouse for analytics, not transactional workloads.

Answer

Amazon Redshift

Answer

Amazon S3

Answer

Amazon RDS for MySQL

Question 10

A company is using Amazon RDS for MySQL and wants to automate backups for point-in-time recovery. Which TWO actions should be taken? (Choose TWO.)

Accepted Answer

Enable automated backups with a retention period.. Options B and D are correct. Automated backups are enabled by default, and the retention period can be set up to 35 days. Option A is wrong because manual snapshots are not automated. Option C is wrong because Multi-AZ is for high availability, not backups. Option E is wrong because AWS Backup is an optional service but not required; RDS native backups suffice.

Answer

Use AWS Backup to schedule backups.

Answer

Enable Multi-AZ deployment.

Answer

Take manual snapshots daily.

Question 11

A company runs a critical application on Amazon RDS for MySQL. To ensure high availability and automatic failover, the database is deployed as a Multi-AZ DB instance. The application uses read-heavy workloads. Which additional configuration should be used to offload read traffic without impacting write performance?

Accepted Answer

Create one or more Read Replicas in different AZs.. Option C is correct because Read Replicas can serve read traffic and reduce load on the primary instance, while Multi-AZ provides high availability. Option A (Multi-AZ for reads) does not offload reads; the standby is not used for reads. Option B (single AZ with larger instance) does not provide high availability. Option D (ElastiCache) caches data but does not serve read replicas for complex queries.

Answer

Use the Multi-AZ standby instance for read queries.

Answer

Use Amazon ElastiCache to cache read queries.

Answer

Change to a Single-AZ deployment with a larger instance size.

Question 12

A data engineering team is designing a data lake on Amazon S3. They need to store raw data in a format that supports schema evolution and is optimized for analytics with Amazon Athena. Which storage format should they use?

Accepted Answer

Parquet. Option B is correct because Parquet is a columnar format that supports schema evolution and is optimized for Athena. Option A (CSV) does not support schema evolution and is less efficient. Option C (Avro) is row-based and not as efficient for columnar queries. Option D (JSON) is text-based and not optimized.

Answer

CSV

Answer

Avro

Answer

JSON

Question 13

Which TWO features of Amazon S3 help protect data from accidental deletion or modification? (Choose two.)

Accepted Answer

S3 MFA Delete. Options A and B are correct because versioning allows recovery of previous versions and MFA delete adds an extra layer of protection. Option C (cross-region replication) is for disaster recovery, not accidental deletion. Option D (default encryption) protects data at rest, not deletion. Option E (lifecycle policies) automate transitions, not protection.

Answer

Lifecycle policies

Answer

Default encryption

Answer

Cross-Region Replication

Question 14

A data engineer is designing a disaster recovery strategy for an Amazon RDS for PostgreSQL database. The primary database is in us-east-1. Which TWO approaches provide cross-region disaster recovery?

Accepted Answer

Configure cross-region automated backups to copy to us-west-2.. Cross-region read replica can be promoted to a primary in another region. Cross-region automated backups can be restored to a different region. Multi-AZ is within a region. Snapshots are manual and region-specific unless copied.

Answer

Take a manual snapshot and copy it to us-west-2 daily.

Answer

Use Amazon S3 cross-region replication for the database export.

Answer

Enable Multi-AZ in us-east-1.

Question 15

A company uses Amazon DynamoDB for a gaming leaderboard. The table has a partition key of 'GameId' and a sort key of 'Score'. The application needs to query the top 10 scores for a given game. Which DynamoDB feature should be used for optimal performance?

Accepted Answer

Create a Global Secondary Index with the same partition key and sort key, then query with ScanIndexForward false.. Option C is correct because a Global Secondary Index with 'GameId' as partition key and 'Score' as sort key allows efficient querying with ScanIndexForward=false to get top scores. Option A is wrong because the base table's sort key is 'Score', but querying by 'GameId' and sorting descending would work but is less efficient if the table has other attributes. However, GSI is specifically for this access pattern. Option B is wrong because DynamoDB Streams is for change data capture, not querying. Option D is wrong because DAX is a caching layer, not a querying feature.

Answer

Use a Query operation on the base table with ScanIndexForward set to false.

Answer

Enable DynamoDB Streams and use a Lambda function to compute the leaderboard.

Answer

Use DynamoDB Accelerator (DAX) to cache the results of a Scan operation.