DEA-C01 Data Store Management Practice Test 30 — 15 Questions

Question 1

A company uses Amazon S3 to store log files that are generated every hour. Each log file is about 1 GB. The logs must be stored for 5 years for compliance. The data engineer wants to minimize storage costs while ensuring that logs can be retrieved within 24 hours for the first year, and within 48 hours thereafter. Which THREE lifecycle actions should the engineer configure? (Choose THREE.)

Accepted Answer

Transition objects to S3 Glacier Deep Archive after 1 year.. Option B is correct because Standard-IA is suitable for infrequently accessed data with immediate retrieval. Option C is correct because Glacier Deep Archive provides low-cost storage with retrieval within 12 hours. Option D is correct because Deep Archive retrieval within 48 hours meets the requirement. Option A is incorrect because Standard is not cost-effective for long-term. Option E is incorrect because deletion before 5 years violates compliance.

Answer

Transition objects to S3 Standard after 30 days.

Answer

Delete objects after 2 years to reduce storage costs.

Question 2

A data engineer at a media company is managing an Amazon RDS for MySQL database that stores user profiles and preferences. The database has been running on a db.r5.large instance with 500 GB of General Purpose SSD (gp2) storage. Recently, the application team has noticed increased query latency during peak hours. Amazon CloudWatch metrics show that the ReadIOPS metric is consistently peaking at 5,000 IOPS, which is near the baseline performance of the gp2 volume (1,500 IOPS baseline for 500 GB, but with bursts up to 3,000 IOPS for short periods). The database is not CPU-bound, and memory utilization is moderate. The data engineer needs to resolve the I/O bottleneck with minimal cost increase. The company is open to changing the storage type or instance class, but wants to avoid over-provisioning. What should the data engineer do?

Accepted Answer

Change the storage type to General Purpose SSD (gp3) and set the provisioned IOPS to 5,000.. Option D is correct because gp3 provides a baseline of 3,000 IOPS and 125 MB/s throughput at no additional cost, and can be increased independently. This would give 5,000 IOPS without the burst limitations of gp2. Option A is incorrect because moving to Provisioned IOPS (io1) would be more expensive and requires provisioning IOPS. Option B is incorrect because increasing instance size to memory-optimized classes does not directly improve IOPS; it adds unnecessary memory cost. Option C is incorrect because Multi-AZ does not improve read IOPS performance; the standby is not used for reads.

Answer

Enable Multi-AZ deployment to offload reads to the standby instance.

Answer

Change the storage type to Provisioned IOPS SSD (io1) and provision 5,000 IOPS.

Answer

Upgrade the instance to a db.r5.xlarge to get more memory and reduce I/O.

Question 3

A startup is building a ride-sharing application that uses Amazon DynamoDB to store trip data. The table has a partition key of 'trip_id' and a sort key of 'status'. The application writes a new item when a trip starts and updates the status when the trip ends. The development team is experiencing high write latency during peak hours. The table is provisioned with 5,000 write capacity units (WCU) and 5,000 read capacity units (RCU). CloudWatch metrics show that WriteThrottleEvents are occurring frequently, but the consumed write capacity is never above 4,000 WCU. The team suspects that the issue is due to hot partitions. How should the data engineer resolve this issue?

Accepted Answer

Modify the application to add a random suffix to the partition key when writing items.. Option C is correct because using a random prefix for the partition key distributes writes across partitions, avoiding hot spots. Option A is incorrect because increasing WCU does not solve the hot partition issue; throttling happens at the partition level. Option B is incorrect because DAX is a cache for reads, not writes. Option D is incorrect because decreasing RCU is unrelated to write throttling.

Answer

Enable DynamoDB Accelerator (DAX) to cache write operations.

Answer

Decrease the provisioned RCU to 2,000 to reduce costs.

Answer

Increase the provisioned WCU to 10,000 to handle the spikes.

Question 4

A company uses Amazon S3 to store sensitive documents. The security team has mandated that all objects must be encrypted at rest using server-side encryption with AWS KMS (SSE-KMS). Additionally, the company wants to ensure that any attempt to upload an unencrypted object is denied. A data engineer has configured a bucket policy that denies PutObject if the encryption header does not include x-amz-server-side-encryption: aws:kms. However, the engineer notices that some objects are still being stored without encryption. Upon investigation, the engineer suspects that the policy is not being evaluated correctly. What should the engineer do to ensure that all objects are encrypted with SSE-KMS?

Accepted Answer

Enable default encryption on the S3 bucket with SSE-KMS.. Option D is correct because enabling default encryption on the S3 bucket with SSE-KMS ensures that any object uploaded without an explicit encryption header is automatically encrypted with SSE-KMS. This closes the gap where the bucket policy condition fails to catch uploads that omit the `x-amz-server-side-encryption` header entirely, as the policy only denies requests with an incorrect header but does not block requests that lack the header altogether. Default encryption applies server-side encryption at the bucket level, making it impossible to store an unencrypted object.

Answer

Use an IAM policy to require encryption instead of a bucket policy.

Answer

Enable S3 Block Public Access settings.

Answer

Add a condition to the bucket policy that checks for aws:SourceVpce.

Question 5

A company is designing a data lake on AWS using Amazon S3. The data includes sensitive customer information that must be encrypted at rest. The company requires that encryption keys be managed by AWS, but the keys must be rotated automatically every year. Which TWO options meet these requirements? (Choose TWO.)

Accepted Answer

Use Server-Side Encryption with Amazon S3-Managed Keys (SSE-S3).. SSE-S3 uses Amazon S3-managed keys with automatic rotation every year. SSE-KMS with automatic key rotation (enabled by default) also meets the key rotation requirement. SSE-C does not use AWS-managed keys. SSE-KMS with manual rotation is not automatic. Client-side encryption does not use AWS keys.

Answer

Use client-side encryption with an AWS KMS key.

Answer

Use Server-Side Encryption with Customer-Provided Keys (SSE-C).

Answer

Use Server-Side Encryption with AWS KMS-Managed Keys (SSE-KMS) with manual key rotation.

Question 6

A company uses Amazon Redshift for its data warehouse. The cluster has multiple node types and is configured with automated snapshots. The company needs to ensure high availability and disaster recovery across AWS Regions. Which THREE actions should the company take to meet these requirements? (Choose THREE.)

Accepted Answer

Restore a snapshot from the secondary Region in the event of a disaster.. Enabling cross-Region snapshot copy, restoring a snapshot to a different Region, and configuring a multi-AZ cluster (if supported) provide high availability and DR. Automated snapshots are already present. Manual snapshots are not needed for DR if automated snapshots are configured. Resizing the cluster does not provide DR.

Answer

Enable automated snapshots with a retention period of at least 1 day.

Answer

Create manual snapshots on a daily basis and copy them to another Region.

Question 7

A data engineer needs to store streaming data from multiple sources into Amazon S3. The data should be organized by source, date, and hour. The engineer wants to minimize processing overhead. Which THREE S3 features should the engineer use to achieve this? (Choose THREE.)

Accepted Answer

S3 Inventory to list objects and their metadata.. S3 prefixes organize objects into a hierarchy. S3 Inventory provides a list of objects. S3 Event Notifications trigger downstream processing. Batch Operations are for bulk actions, not organization. Object Lock is for retention. S3 Select is for querying within files.

Answer

S3 Object Lock to prevent object modifications.

Answer

S3 Batch Operations to rename objects after upload.

Question 8

A company uses Amazon DynamoDB as a key-value store for a high-traffic application. The table has a provisioned read capacity of 10,000 RCUs and write capacity of 5,000 WCUs. The application experiences occasional throttling during peak hours. Which TWO actions can reduce throttling without changing the application code? (Choose TWO.)

Accepted Answer

Enable DynamoDB Auto Scaling for both read and write capacity.. Enabling Auto Scaling adjusts capacity automatically. Adding a read replica (DAX) reduces read load. Adding a Global Table does not increase capacity. Changing to on-demand mode can help but may increase cost. Reducing read consistency is not recommended.

Answer

Switch to on-demand capacity mode for the table.

Answer

Change the read consistency model from eventually consistent to strongly consistent.

Answer

Use DynamoDB Global Tables to distribute the workload across regions.

Question 9

A company runs an Amazon RDS for PostgreSQL instance for an OLTP application. The database size is 500 GB. The company wants to minimize downtime during backups and ensure point-in-time recovery (PITR) for the last 7 days. Which TWO features should the company use? (Choose TWO.)

Accepted Answer

Enable Multi-AZ deployment for high availability.. Automated backups with a 7-day retention provide PITR. Multi-AZ deployment ensures high availability and reduces downtime during backups. Manual snapshots are not needed. Enhanced Monitoring is for performance. Read replicas are for read scaling, not backup.

Answer

Create a read replica in a different Availability Zone.

Answer

Create daily manual snapshots and copy them to another region.

Answer

Enable Enhanced Monitoring to track backup progress.

Question 10

A company uses AWS Glue to catalog data stored in Amazon S3. The data is in Parquet format and partitioned by date. The company wants to improve query performance in Amazon Athena and reduce costs. Which THREE actions should the company take? (Choose THREE.)

Accepted Answer

Partition the data by date so Athena can use partition pruning.. Using columnar formats like Parquet improves performance and reduces scanned data. Partitioning by date allows Athena to prune partitions. Compressing data reduces storage and scan costs. Converting to JSON would hurt performance. Increasing partition count may help but is not a guarantee. Using Glue DataBrew is for data preparation, not performance optimization.

Answer

Convert the data to JSON format for better schema evolution.

Answer

Use Glue DataBrew to clean the data before querying.

Question 11

A company is migrating a MySQL database to Amazon RDS for MySQL. The database is 2 TB in size and the company can only afford minimal downtime. The migration must be secure and use AWS DMS. Which TWO configuration steps are required? (Choose TWO.)

Accepted Answer

Create a source endpoint pointing to the on-premises MySQL database.. AWS DMS requires a source endpoint (source database connection) and a target endpoint (RDS instance). Option C is the source endpoint, option D is the target endpoint. The other options are not required for DMS: SSL/TLS is optional but recommended, replication instance is created by DMS, and VPC peering is not typically needed if using the same VPC.

Answer

Configure SSL/TLS encryption for the DMS endpoints.

Answer

Set up VPC peering between the on-premises network and the Amazon VPC.

Answer

Create a DMS replication instance.

Question 12

A large e-commerce company uses Amazon DynamoDB to store shopping cart data. The table has a partition key of 'user_id' and a sort key of 'item_id'. The application performs frequent updates to the 'quantity' attribute for items in a user's cart. Recently, the operations team noticed that write requests are being throttled during peak shopping hours. The table is provisioned with 10,000 write capacity units (WCUs) and uses DynamoDB Accelerator (DAX) for read caching. The data engineer suspects that the throttling is due to hot partitions. The application uses a single AWS SDK client configured with retries. After reviewing the Amazon CloudWatch metrics, the engineer sees that the WriteThrottleEvents metric spikes for a few partition keys. The table has a high number of partitions. What should the data engineer do to resolve the throttling issue with minimal application changes?

Accepted Answer

Configure DynamoDB Auto Scaling with a maximum WCU setting of 20,000 and a target utilization of 70%.. Option D is correct because using DynamoDB Auto Scaling with a higher maximum WCUs allows the table to scale up during peak demand, addressing hot partitions without code changes. Option A is wrong because increasing WCUs manually does not adapt to variable traffic. Option B is wrong because DAX is for reads, not writes. Option C is wrong because Global Tables replicate data but do not increase write capacity.

Answer

Increase the provisioned write capacity to 20,000 WCUs permanently.

Answer

Enable DynamoDB Global Tables to distribute writes across regions.

Answer

Add more nodes to the DAX cluster to offload write traffic.

Question 13

A media company stores video files in Amazon S3 buckets organized by content type. The company has a requirement to automatically archive files that are older than 90 days to Amazon S3 Glacier Deep Archive to reduce costs. However, the company wants to retain the ability to restore files within 12 hours if needed. The data engineer creates an S3 Lifecycle policy to transition objects to Glacier Deep Archive after 90 days. After deploying the policy, the engineer notices that the storage costs have not decreased significantly. On reviewing the bucket metrics, the engineer sees that many objects are being deleted directly by users before the lifecycle policy takes effect. The company needs to enforce the lifecycle policy and prevent premature deletions. What should the data engineer do to enforce the lifecycle policy?

Accepted Answer

Enable S3 Versioning on the bucket and add a lifecycle rule to transition noncurrent versions to Glacier Deep Archive after 90 days.. Option A is correct because an S3 Lifecycle policy with a noncurrent version transition will move older versions to Deep Archive, and enabling S3 Versioning ensures that deletions create delete markers rather than permanently deleting objects. Option B is wrong because MFA Delete is for extra security, not for lifecycle enforcement. Option C is wrong because Object Lock prevents object deletion entirely, which may not be desired. Option D is wrong because S3 Glacier Select is for querying archived data, not for lifecycle management.

Answer

Apply an S3 Object Lock retention policy with a default retention mode of GOVERNANCE and a retention period of 90 days.

Answer

Enable S3 Multi-Factor Authentication (MFA) Delete on the bucket to require MFA for all delete operations.

Answer

Use S3 Glacier Select to query the objects and restore them if needed.

Question 14

A startup is building a real-time analytics application using Amazon Kinesis Data Streams and Amazon Kinesis Data Analytics. The application processes clickstream data from a website. The data is also stored in Amazon S3 for historical analysis. The company uses an S3 bucket with a lifecycle policy that transitions objects to Amazon S3 Glacier Deep Archive after 30 days. The data engineering team has configured a Kinesis Data Firehose delivery stream to write data to the S3 bucket. The team notices that the data in S3 is not being transitioned to Glacier Deep Archive after 30 days. The lifecycle policy is correctly configured and has been verified. What is the most likely cause of this issue?

Accepted Answer

The S3 lifecycle rule is configured with a filter that does not match the prefix used by Kinesis Data Firehose.. Option C is correct because Kinesis Data Firehose writes data with a prefix that includes the date, but it often uses the delivery stream's timestamp rather than the object creation date. The lifecycle rule is based on the object creation date. If the prefix does not match the rule filter, the rule may not apply. Option A is wrong because S3 Batch Operations are not related to lifecycle transitions. Option B is wrong because Glacier Deep Archive does have a minimum 90-day storage charge, but the lifecycle rule can still transition after 30 days (though you'll pay a penalty). Option D is wrong because S3 Intelligent-Tiering is an alternative storage class, not a requirement.

Answer

The Glacier Deep Archive storage class requires a minimum 90-day storage period, so the lifecycle policy cannot transition objects after 30 days.

Answer

The S3 bucket is not enabled for S3 Intelligent-Tiering, which is required for lifecycle transitions to Glacier Deep Archive.

Answer

The S3 bucket does not have S3 Batch Operations enabled to invoke the lifecycle policy.

Question 15

A healthcare company uses Amazon RDS for PostgreSQL to store patient records. The database has a size of 1 TB and is running on a db.r5.large instance. The company requires that the database be highly available and have automated backups with point-in-time recovery (PITR) for the last 35 days. The operations team has configured Multi-AZ deployment and automated backups with a 35-day retention period. During a recent disaster simulation, the team attempted to restore the database to a point in time from 30 days ago. The restore operation failed because the backup was not available. On investigation, the team found that the automated backups were being deleted before the retention period ended. The team also noticed that the database has a large number of transaction logs generating a high volume of write activity. What is the most likely cause of the backups being deleted prematurely?

Accepted Answer

The RDS instance was deleted, which automatically deletes all automated backups.. Option D is correct because automated backups are retained based on the backup retention period. However, if the database instance is deleted, all automated backups are also deleted. Option A is wrong because manual snapshots are separate from automated backups. Option B is wrong because the backup window does not affect retention. Option C is wrong because Multi-AZ automatically performs backups from the standby, but the retention is still enforced.

Answer

The automated backup window was set to a time that conflicted with the database maintenance window.

Answer

The Multi-AZ deployment was not enabled during the backup process, causing backups to fail.

Answer

The database had manual snapshots that were deleted manually by the operations team.