DEA-C01 Data Store Management Practice Test 22 — 15 Questions

Question 1

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

Accepted Answer

S3 MFA Delete. C is correct because S3 MFA Delete requires multi-factor authentication for permanent deletion of objects or suspension of versioning, adding a critical layer of protection against accidental or malicious deletions. D is correct because S3 Object Versioning preserves every version of an object, allowing recovery from accidental overwrites or deletions by restoring a previous version.

Answer

Lifecycle policies

Answer

Default encryption

Answer

Cross-Region Replication

Question 2

A company is using Amazon S3 to store large amounts of archival data. The data is accessed infrequently but must be immediately retrievable when needed. Which storage class is the most cost-effective choice?

Accepted Answer

S3 Standard-IA. S3 Standard-IA (Infrequent Access) is the most cost-effective choice because it offers lower storage costs than S3 Standard while still providing millisecond first-byte latency for immediate retrieval. The data is accessed infrequently but requires instant availability, which matches the IA use case exactly.

Answer

S3 Standard

Answer

S3 Glacier Deep Archive

Answer

S3 Intelligent-Tiering

Question 3

A data engineer needs to set up a new Amazon RDS for PostgreSQL database for a production workload. The database must be highly available and resilient to a single Availability Zone failure. Which configuration should the engineer choose?

Accepted Answer

Multi-AZ deployment with one standby in a different AZ. A Multi-AZ deployment for Amazon RDS PostgreSQL automatically provisions and maintains a synchronous standby replica in a different Availability Zone. This configuration provides automatic failover in the event of an AZ failure, ensuring high availability and resilience without manual intervention. The synchronous replication ensures zero data loss during failover, which is critical for production workloads.

Answer

Single-AZ with automated backups

Answer

Multi-AZ with two readable standbys

Answer

Single-AZ with a read replica

Question 4

A company wants to migrate its on-premises MySQL database to Amazon RDS for MySQL with minimal downtime. Which AWS service should be used for the migration?

Accepted Answer

AWS Database Migration Service (DMS). AWS Database Migration Service (DMS) is purpose-built for migrating databases to AWS with minimal downtime by using ongoing replication (change data capture, CDC) from the source MySQL database to the target Amazon RDS for MySQL instance. This allows the source to remain fully operational during the migration, meeting the minimal-downtime requirement.

Answer

AWS Schema Conversion Tool (SCT)

Answer

AWS DataSync

Answer

AWS Direct Connect

Question 5

A data engineer is troubleshooting an Amazon DynamoDB table that has frequent throttling exceptions for write requests. The table has auto scaling enabled. What is the most likely cause?

Accepted Answer

The partition key is causing a hot partition. Auto scaling adjusts capacity based on utilization, but it cannot prevent throttling caused by a hot partition. If a single partition key value receives a disproportionate share of write traffic, that partition's throughput limit (3,000 WCU or 10 MB per partition) is exceeded, triggering ProvisionedThroughputExceededException. Auto scaling operates at the table level, not per partition, so it cannot resolve this imbalance.

Answer

The table's read capacity is set too low

Answer

The table's auto scaling is disabled

Answer

The table is using global tables without conflict resolution

Question 6

A company stores sensitive data in Amazon S3. They need to ensure that all objects are encrypted at rest. Which approach meets this requirement with minimal effort?

Accepted Answer

Enable default encryption on the S3 bucket with SSE-S3. Enabling default encryption on an S3 bucket with SSE-S3 (Server-Side Encryption with S3-Managed Keys) automatically encrypts all objects at rest using AES-256, with no additional effort from the user. This ensures that any object uploaded without explicit encryption headers is encrypted by default, meeting the requirement with minimal configuration overhead.

Answer

Use client-side encryption before uploading

Answer

Enable S3 Versioning and MFA Delete

Answer

Use a bucket policy to deny PutObject without encryption

Question 7

A data engineer is designing a data lake on Amazon S3. Which feature should be used to manage the lifecycle of objects and move them to cheaper storage classes automatically?

Accepted Answer

S3 Lifecycle policies. S3 Lifecycle policies are the correct feature for automatically managing object lifecycles and transitioning objects to cheaper storage classes (e.g., from S3 Standard to S3 Glacier Deep Archive) based on age or other rules. This directly meets the requirement to move objects to cost-optimized storage without manual intervention.

Answer

S3 Object Lock

Answer

S3 Storage Class Analysis

Answer

S3 Inventory

Question 8

A company has an Amazon RDS for MySQL database that is experiencing performance issues due to a large number of read requests. The application is read-heavy and can tolerate eventually consistent reads. Which action will reduce the load on the primary database with the least operational overhead?

Accepted Answer

Create a read replica in the same region. Creating a read replica in the same region offloads read traffic from the primary RDS instance to a read-only copy, which directly addresses the read-heavy workload. Since the application can tolerate eventually consistent reads, the slight replication lag is acceptable, and this solution requires minimal operational overhead—just a few clicks in the AWS console or a single API call—without any application code changes.

Answer

Use Amazon ElastiCache for caching

Answer

Enable Multi-AZ deployment

Answer

Increase the instance size of the primary DB

Question 9

A data engineer needs to store JSON documents that are accessed by a key-value pattern. The workload requires single-digit millisecond latency at any scale. Which AWS service is most appropriate?

Accepted Answer

Amazon DynamoDB. Amazon DynamoDB is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale. It is optimized for key-value access patterns, making it the ideal choice for storing and retrieving JSON documents by a primary key with consistent low latency.

Answer

Amazon DocumentDB (with MongoDB compatibility)

Answer

Amazon RDS for PostgreSQL

Answer

Amazon Neptune

Question 10

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. The condition key `s3:x-amz-server-side-encryption` with value `aws:kms` enforces that objects uploaded to the S3 bucket must be encrypted using AWS KMS (SSE-KMS). This bucket policy condition ensures that any PUT request includes the `x-amz-server-side-encryption` header set to `aws:kms`, thereby enforcing encryption at rest with KMS-managed keys.

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 11

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.. Amazon RDS supports cross-region automated backups, which automatically copy backup data (snapshots and transaction logs) from the primary region (us-east-1) to a secondary region (us-west-2). This provides a fully managed, automated disaster recovery solution that allows point-in-time recovery in the secondary region without manual intervention.

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 12

A company is migrating a large Oracle data warehouse to Amazon Redshift. Which THREE considerations are important for optimizing the Redshift cluster?

Accepted Answer

Defining appropriate sort keys for the tables.. Sort keys in Amazon Redshift determine the physical order of data on disk, which directly impacts the efficiency of range-restricted queries and compression. By defining appropriate sort keys (compound or interleaved), the query optimizer can use zone maps to skip large blocks of data that don't match the filter criteria, significantly reducing the number of blocks scanned and improving query performance.

Answer

Purchasing reserved instances for the cluster.

Answer

Using columnar storage format.

Question 13

A data engineer is setting up Amazon S3 event notifications to trigger an AWS Lambda function when new objects are uploaded. Which TWO actions are required to enable this?

Accepted Answer

Add a resource-based policy to the Lambda function to allow S3 to invoke it.. Lambda functions use a resource-based policy (also known as a function policy) to grant permissions to other AWS services, such as S3, to invoke the function. Without this policy, S3 will receive an access denied error when trying to trigger the Lambda function. Option D is correct because you must configure an S3 event notification on the bucket for the `s3:ObjectCreated:*` event type to instruct S3 to send a notification to the Lambda function when new objects are uploaded.

Answer

Enable S3 versioning on the bucket.

Answer

Create an S3 bucket policy that grants S3 permission to invoke Lambda.

Answer

Set up an Amazon CloudWatch Events rule to detect S3 uploads.

Question 14

The exhibit shows an S3 bucket policy. What is the effect of this policy?

Accepted Answer

Allows only GetObject and PutObject over HTTPS.. The S3 bucket policy in the exhibit uses a condition key `aws:SecureTransport` set to `true`, which restricts access to HTTPS only. The `Effect` is `Allow` for `s3:GetObject` and `s3:PutObject` actions, meaning only these two actions are permitted over HTTPS. This matches option D.

Answer

Allows all S3 actions over HTTPS only.

Answer

Allows all S3 actions to the bucket over any protocol.

Answer

Denies all S3 actions to the bucket.

Question 15

The exhibit shows the output of describe-table for a DynamoDB table. The table is used for a reporting job that queries by 'pk' and filters on 'sk' using a range condition. The job is running slowly. What is the most likely cause?

Accepted Answer

The provisioned read capacity is too low.. The describe-table output shows the table has a primary key composed of 'pk' (partition key) and 'sk' (sort key), which is ideal for the query pattern described (query by 'pk' and filter on 'sk' with a range condition). The job is running slowly, and the most likely cause is insufficient provisioned read capacity, as the reporting job may be consuming more read capacity units than provisioned, leading to throttling and slower performance.

Answer

The table lacks a global secondary index (GSI).

Answer

The table uses provisioned throughput instead of on-demand.

Answer

The table needs a local secondary index (LSI) on 'sk'.