DEA-C01 Data Store Management Practice Test 9 — 15 Questions

Question 1

A company is using AWS Glue to run ETL jobs that write data to an Amazon S3 data lake. The jobs are failing with '503 Slow Down' errors. The data engineering team has already implemented retries. What is the BEST long-term solution?

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

Accepted Answer

Implement a backoff strategy to reduce the request rate.. The '503 Slow Down' error from Amazon S3 indicates that the request rate is too high and S3 is throttling the requests. The best long-term solution is to implement a backoff strategy (exponential backoff) to reduce the request rate, which allows the Glue job to automatically slow down and retry with increasing delays, aligning with S3's request rate limits and avoiding sustained throttling.

Answer

Enable S3 Transfer Acceleration.

Answer

Use S3 multipart upload for all objects.

Answer

Increase the number of retries in the Glue job.

Question 2

A company is using Amazon Kinesis Data Streams to ingest real-time clickstream data. The data must be stored in Amazon S3 in near real-time with minimal overhead. Which THREE steps should the data engineer take to achieve this? (Choose THREE.)

Accepted Answer

Configure a Lambda function to transform data before delivery to S3.. Option B is correct because Amazon Kinesis Data Firehose is the fully managed service designed to load streaming data from Kinesis Data Streams into destinations like Amazon S3 with near real-time delivery and minimal operational overhead. Option A is correct because Firehose supports invoking an AWS Lambda function to transform records (for example, converting formats or enriching data) before delivering them to S3, which meets the requirement to transform data with minimal overhead. Option E is correct because Firehose can apply GZIP compression to the data it writes to S3, reducing storage size and cost while requiring only a configuration setting. Option C is not appropriate because Kinesis Data Analytics is for running SQL or Apache Flink analytics over streaming data, not for the simple managed delivery of raw or transformed records to S3. Option D is not relevant because S3 cross-region replication copies objects between buckets for durability or latency purposes and does not address ingesting Kinesis Data Streams into S3 in near real-time.

Answer

Use Kinesis Data Analytics to process and store data in S3.

Answer

Enable S3 cross-region replication for the destination bucket.

Question 3

A company is evaluating Amazon DynamoDB for a new application. The application requires single-digit millisecond latency for read and write operations. Which TWO DynamoDB features should the company enable to achieve this? (Choose TWO.)

Accepted Answer

Use DAX with Write-Through caching.. Option D is correct because DynamoDB Accelerator (DAX) is a fully managed, in-memory cache purpose-built for DynamoDB that delivers microsecond response times for eventually consistent reads, and when combined with the underlying table it helps sustain single-digit millisecond latency at high request rates. Option A is correct because using DAX with write-through caching ensures that writes are propagated through the DAX cluster to the DynamoDB table while keeping the cache coherent, so subsequent reads are served from the in-memory cache with microsecond latency and writes still meet the single-digit millisecond requirement. Option B is not correct because Global Tables provide multi-Region, active-active replication for disaster recovery and low-latency global access, but they do not by themselves guarantee single-digit millisecond latency for a single-Region workload. Option C is not correct because DynamoDB Streams captures item-level changes for event-driven processing and replication, not for reducing read/write latency. Option E is not correct because auto-scaling adjusts provisioned read and write capacity to match traffic patterns, which controls throughput and cost but does not deliver the microsecond-level cache acceleration needed for consistently low latency.

Answer

Enable DynamoDB Global Tables.

Answer

Enable DynamoDB Streams.

Answer

Enable auto-scaling for read and write capacity.

Question 4

The exhibit shows the lifecycle configuration for an S3 bucket. Objects in the bucket are 200 days old on average. What will happen to the objects?

Accepted Answer

Objects are in GLACIER now and will be deleted after 365 days from creation.. The lifecycle configuration shows a current version action to transition to GLACIOR (a misspelling of GLACIER) immediately (0 days after creation) and an expiration action to permanently delete the object 365 days after creation. Since the objects are already 200 days old on average, they have already been transitioned to GLACIER storage class. The expiration rule will delete them 365 days from their creation date, not from the current time.

Answer

Objects will be transitioned to GLACIER after 90 days and deleted after 365 days.

Answer

Objects will be transitioned to GLACIER after 200 days and deleted after 365 days.

Answer

Objects will be deleted after 90 days.

Question 5

The exhibit shows the output of describe-table for a DynamoDB table. The application is experiencing throttling errors when reading data. What is the MOST likely cause?

Accepted Answer

The table's provisioned read capacity is too low.. The describe-table output shows the table has provisioned read capacity set to 5, but the application is experiencing throttling errors. Throttling occurs when read requests exceed the provisioned read capacity units (RCUs). Increasing the read capacity or implementing retries with exponential backoff would resolve this. The throttling is directly caused by insufficient provisioned read capacity for the workload.

Answer

The sort key is not used correctly for queries.

Answer

The table has a hot partition due to the HASH key.

Answer

The table size is too large, causing slow reads.

Question 6

A company is using Amazon S3 to store sensitive data. They need to automatically transition objects to S3 Glacier Deep Archive after 90 days and delete them after 7 years. Which S3 lifecycle configuration action should be used?

Accepted Answer

Transition. The S3 lifecycle 'Transition' action is specifically designed to move objects between storage classes. To automatically move objects to S3 Glacier Deep Archive after 90 days, you define a transition rule with a 'Days' value of 90 and a 'StorageClass' of 'DEEP_ARCHIVE'. This action directly meets the requirement for transitioning data to a colder storage tier.

Answer

AbortIncompleteMultipartUpload

Answer

Expiration

Answer

NoncurrentVersionExpiration

Question 7

A data engineer is designing a data store for a time-series application that requires sub-millisecond read latency for the latest data and high ingestion rates. Which AWS service is most suitable?

Accepted Answer

Amazon Timestream. Amazon Timestream is purpose-built for time-series data, offering sub-millisecond read latency for recent data via its in-memory store and supporting high ingestion rates with automatic partitioning and tiering. It is the most suitable choice because it natively handles time-series workloads without requiring manual tuning or schema optimization.

Answer

Amazon DynamoDB

Answer

Amazon ElastiCache for Redis

Answer

Amazon RDS for PostgreSQL

Question 8

A company is migrating an on-premises Hadoop cluster to AWS. The data is stored in HDFS and needs to be accessible by both Amazon EMR and Amazon Redshift Spectrum. Which storage solution is most cost-effective and scalable?

Accepted Answer

Amazon Simple Storage Service (S3). Amazon S3 is the most cost-effective and scalable storage solution for this use case because it provides native integration with both Amazon EMR (via S3A connector or EMRFS) and Amazon Redshift Spectrum (via external tables). Unlike HDFS, S3 decouples compute from storage, allowing you to pay only for the data stored and the compute resources used, with virtually unlimited scalability and 99.999999999% durability.

Answer

Amazon FSx for HDFS

Answer

Amazon Elastic Block Store (EBS)

Answer

Amazon Elastic File System (EFS)

Question 9

A data engineer is troubleshooting an Amazon Redshift cluster that is experiencing slow query performance. The engineer notices that the disk space is heavily utilized and queries are spilling to disk. What is the most cost-effective solution to improve performance?

Accepted Answer

Resize the cluster to a larger node type or add nodes. When queries spill to disk due to heavy disk utilization, the root cause is insufficient memory or compute capacity relative to the workload. Resizing the cluster (adding nodes or moving to a larger node type) directly increases available memory and CPU, reducing or eliminating disk spill and improving query performance. This is the most cost-effective solution because it scales resources proportionally without requiring manual tuning or schema changes.

Answer

Run VACUUM command to reclaim space

Answer

Change distribution style to KEY

Answer

Apply compression encoding to tables

Question 10

A company needs to store streaming data from IoT devices with a retention period of 7 days for real-time analysis. Which AWS service is most suitable?

Accepted Answer

Amazon Kinesis Data Streams. Amazon Kinesis Data Streams is the most suitable service because it is designed for real-time ingestion and processing of streaming data, such as IoT device telemetry, with a default retention period of 24 hours, extendable up to 365 days. The requirement for a 7-day retention period for real-time analysis aligns perfectly with Kinesis Data Streams' ability to retain data for exactly that duration, allowing consumers to process records in near real-time using the Kinesis Client Library (KCL) or AWS Lambda.

Answer

Amazon DynamoDB

Answer

Amazon Kinesis Data Firehose

Answer

Amazon S3

Question 11

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.. An S3 Lifecycle policy can automate both the transition of objects to S3 Glacier Deep Archive after 90 days and their expiration (permanent deletion) after 7 years. This is the most cost-effective approach as it eliminates manual effort and leverages S3's native, serverless lifecycle management, which incurs no additional cost beyond the storage and transition fees.

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 12

A company runs a critical transactional database on Amazon RDS for PostgreSQL. They need to achieve high availability with automatic failover to a different AWS Region in case of a regional outage. Which solution meets these requirements?

Accepted Answer

Use Amazon Aurora Global Database with a primary cluster in one Region and a secondary in another.. Amazon Aurora Global Database is designed for cross-Region disaster recovery, replicating data with a typical latency of under one second and providing automatic failover from the primary Region to a secondary Region. This meets the requirement of high availability with automatic failover during a regional outage, unlike standard RDS options which lack built-in cross-Region automatic failover.

Answer

Create a cross-Region Read Replica and promote it during a disaster.

Answer

Take daily automated snapshots and restore them in another Region.

Answer

Deploy the RDS instance in a Multi-AZ configuration.

Question 13

A company is using Amazon S3 to store sensitive financial data. They need to ensure that all objects are encrypted at rest. Which TWO methods can achieve this? (Choose TWO.)

Accepted Answer

Use SSE-KMS to encrypt objects with AWS KMS.. Option C is correct because SSE-KMS encrypts objects at rest using AWS KMS-managed keys, providing server-side encryption with strong key management and auditability via CloudTrail, which satisfies the requirement for encryption at rest. Option E is correct because enabling default encryption with SSE-S3 (AES-256) automatically encrypts every object at rest when it is stored in the bucket, ensuring all objects are protected without relying on the uploader. Option A is incorrect because S3 Transfer Acceleration only speeds up uploads using AWS edge locations and does not encrypt data at rest. Option B is incorrect because a bucket policy denying unencrypted PutObject requests enforces encryption on upload but does not itself encrypt objects at rest. Option D is incorrect because client-side encryption is performed by the customer before uploading, so it is not an S3-managed at-rest encryption method and does not by itself guarantee all objects are encrypted.

Answer

Enable S3 Transfer Acceleration on the bucket.

Answer

Apply a bucket policy that denies PutObject without encryption.

Answer

Use client-side encryption before uploading objects.

Question 14

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.. Option C is correct because DynamoDB Global Tables provide multi-Region, active-active replication with low latency, which is exactly what the scenario requires for cross-Region replication and reads from any Region. Option A is correct because with Global Tables, applications can use the Regional DynamoDB endpoint in any Region to read and write locally, achieving low-latency access from any Region. Option D is correct because Global Tables rely on DynamoDB Streams to capture item-level changes and propagate them to replica tables in other Regions, so Streams must be enabled on the table. Option B is not correct because TTL only deletes expired items and does not contribute to cross-Region replication or low-latency multi-Region reads. Option E is not correct because DAX is an in-memory read/write cache that reduces read latency within a Region but does not replicate data across Regions or enable multi-Region reads.

Answer

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

Answer

Deploy DynamoDB Accelerator (DAX) in each Region.

Question 15

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.. Option A is correct because enabling automated backups on an Amazon RDS for MySQL instance is what activates the continuous, automatic backup of the DB instance and its transaction logs, which is the foundation for point-in-time recovery (PITR). Option C is correct because the backup retention period (set in days, from 1 to 35) defines the window within which you can restore to any specific second using PITR; setting it to the desired number of days ensures the required recovery range is available. Together, enabling automated backups and configuring the retention period are the two required actions to automate backups for PITR on RDS MySQL. Option B is not required because AWS Backup is an optional centralized service and does not by itself enable RDS native PITR. Option D is not correct because Multi-AZ provides high availability via a synchronous standby, not the backup/PITR mechanism. Option E is not correct because manual snapshots are user-initiated, do not capture continuous transaction logs, and therefore do not support point-in-time recovery.

Answer

Use AWS Backup to schedule backups.

Answer

Enable Multi-AZ deployment.

Answer

Take manual snapshots daily.