AZ-204 Develop for Azure storage Practice Test 3 — 15 Questions

Question 1

You are developing an IoT solution that stores device metadata (device ID, location, firmware version, last seen timestamp) in Azure Table Storage. Each device has a unique DeviceId and a Timestamp. You need to design the PartitionKey and RowKey to optimize query performance for the following query: Retrieve all firmware versions for devices in a specific city that were last seen within the last 24 hours. The query must be efficient (partition scan minimized). Which key design is most appropriate?

Accepted Answer

PartitionKey = City, RowKey = Inverted timestamp (e.g., DateTime.MaxValue.Ticks - Timestamp.Ticks). Option B is correct because it uses City as the PartitionKey, ensuring all devices in the same city are in a single partition, and an inverted timestamp as the RowKey, which allows efficient range queries for the last 24 hours. Azure Table Storage sorts entities by RowKey within a partition, so querying for RowKey values greater than the inverted timestamp for 24 hours ago retrieves only the relevant rows without scanning the entire partition.

Answer

PartitionKey = City, RowKey = DeviceId_Timestamp (e.g., "device123_2023-10-01T12:00:00")

Answer

PartitionKey = DeviceId, RowKey = Timestamp

Answer

PartitionKey = City, RowKey = DeviceId

Question 2

You are designing a solution to store user-uploaded images. The images are accessed infrequently (a few times per month) and must be available for download within seconds when requested. You need to minimize storage costs while meeting the access requirements. Which Azure Blob Storage access tier should you choose for the container?

Accepted Answer

Cool tier. The Cool tier is optimal because the images are accessed infrequently (a few times per month) but require immediate download within seconds. Cool tier offers lower storage costs than Hot tier while maintaining low-latency access (milliseconds), meeting the access requirement without incurring the higher storage cost of Hot tier.

Answer

Hot tier

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Cold tier

Answer

Archive tier

Question 3

You are designing an Azure Table Storage table to store temperature readings from IoT devices. Each reading includes a device ID (string), timestamp (datetime), temperature value, and location. You need to optimize the table design for this query: "Retrieve all temperature readings for a specific device ID within a given one-hour time range." The query must be efficient and minimize partition scans. Which PartitionKey and RowKey combination should you use?

Accepted Answer

PartitionKey = device ID, RowKey = timestamp (formatted as inverted ticks). Option A is correct because using device ID as the PartitionKey ensures all readings for a specific device are in the same partition, allowing efficient point queries. Using timestamp formatted as inverted ticks (e.g., DateTime.MaxValue.Ticks - DateTime.UtcNow.Ticks) as the RowKey enables range queries within a one-hour window by leveraging the lexicographic ordering of RowKey values, minimizing partition scans.

Answer

PartitionKey = timestamp (rolled up to day), RowKey = device ID

Answer

PartitionKey = location, RowKey = device ID

Answer

PartitionKey = device ID + timestamp (composite), RowKey = empty

Question 4

You are designing a solution that needs to react to changes in an Azure Cosmos DB container in real-time. Whenever a new document is inserted or updated, a downstream service must be triggered to process the change. You want to build a serverless solution that reliably captures each change exactly once. Which Azure Cosmos DB feature should you use?

Accepted Answer

Change feed. The Change feed in Azure Cosmos DB is designed to capture document-level changes (inserts and updates) in the order they occur and provides an event-driven, serverless mechanism to reliably process each change exactly once. It integrates natively with Azure Functions, enabling real-time reactions without polling or custom tracking.

Answer

Stored procedures

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T-SQL queries

Answer

Triggers

Question 5

Your IoT solution generates billions of small telemetry entries (each ~100 bytes). Data is written once and rarely updated. You need to run analytical queries on the last 30 days of data daily, scanning large ranges by timestamp, requiring sub-second response times. You want the lowest storage cost. Which Azure Storage solution should you use?

Accepted Answer

Azure Table Storage. Azure Table Storage is correct because it is a NoSQL key-value store optimized for high-volume, low-cost storage of structured data like telemetry entries. It supports efficient range queries on the partition key (e.g., timestamp) and row key, enabling sub-second scans of large date ranges. Its storage cost is the lowest among Azure storage options for this workload, as it charges only for consumed capacity with no minimum throughput commitments.

Answer

Azure Blob Storage

Answer

Azure Cosmos DB

Answer

Azure Data Lake Storage

Question 6

You need to store temperature readings from IoT devices in Azure Table Storage. Each reading includes a device ID (string), timestamp (datetime), temperature value, and location. You must optimize for the query: "Retrieve all temperature readings for a specific device ID within a given one-hour time range." Which PartitionKey and RowKey combination should you use?

Accepted Answer

PartitionKey = DeviceId, RowKey = Timestamp. Option A is correct because Azure Table Storage queries are most efficient when the PartitionKey and RowKey are chosen to match the query pattern. By using DeviceId as the PartitionKey, all readings for a specific device are stored in the same partition, enabling fast partition-level scans. Using Timestamp as the RowKey allows efficient range queries within a one-hour window using RowKey comparisons, which is the optimal design for time-range queries on a single device.

Answer

PartitionKey = Location, RowKey = DeviceId

Answer

PartitionKey = Temperature, RowKey = Timestamp

Answer

PartitionKey = DeviceId + Timestamp, RowKey = empty

Question 7

You develop a C# application that stores sensitive documents in Azure Blob Storage. You need to generate a time-limited shared access signature (SAS) that allows a client to only read and list blobs in a specific container. The SAS must be valid for exactly 1 hour from the current time. Which code snippet correctly creates the SAS? (Assume BlobServiceClient and BlobContainerClient are properly initialized.)

Accepted Answer

var sasBuilder = new BlobSasBuilder { BlobContainerName = containerName, Resource = "c", StartsOn = DateTimeOffset.UtcNow, ExpiresOn = DateTimeOffset.UtcNow.AddHours(1), Permissions = BlobContainerSasPermissions.Read | BlobContainerSasPermissions.List }; Uri sasUri = containerClient.GenerateSasUri(sasBuilder);. Option A is correct because it sets the `Resource` property to "c" for container-level SAS, uses `StartsOn` as the current UTC time, `ExpiresOn` exactly 1 hour later, and specifies only `Read` and `List` permissions via the `BlobContainerSasPermissions` enum. This combination generates a time-limited SAS URI that allows a client to read and list blobs within the specified container for exactly one hour.

Answer

var sasBuilder = new BlobSasBuilder { BlobContainerName = containerName, Resource = "b", StartsOn = DateTimeOffset.UtcNow, ExpiresOn = DateTimeOffset.UtcNow.AddHours(1), Permissions = BlobContainerSasPermissions.Read | BlobContainerSasPermissions.List }; Uri sasUri = containerClient.GenerateSasUri(sasBuilder);

Answer

var sasBuilder = new BlobSasBuilder { BlobContainerName = containerName, Resource = "c", StartsOn = DateTimeOffset.UtcNow, ExpiresOn = DateTimeOffset.UtcNow.AddHours(1), Permissions = BlobContainerSasPermissions.All }; Uri sasUri = containerClient.GenerateSasUri(sasBuilder);

Answer

var sasBuilder = new BlobSasBuilder { BlobContainerName = containerName, Resource = "c", StartsOn = DateTimeOffset.UtcNow.AddDays(-1), ExpiresOn = DateTimeOffset.UtcNow.AddHours(1), Permissions = BlobContainerSasPermissions.Read | BlobContainerSasPermissions.List }; Uri sasUri = containerClient.GenerateSasUri(sasBuilder);

Question 8

You are developing a solution that requires multiple Azure virtual machines to access the same set of files concurrently. The files are updated frequently and must be accessible with low latency. You need to choose a shared storage solution that integrates with Microsoft Entra ID (Microsoft Entra ID) for authentication. Which Azure storage solution should you use?

Accepted Answer

Azure Files shares.. Azure Files shares provide fully managed SMB and NFS file shares that can be accessed concurrently by multiple Azure VMs with low latency. They support identity-based authentication using Microsoft Entra ID (formerly Azure AD) over SMB, enabling granular access control via RBAC and NTFS ACLs. This makes Azure Files the correct choice for a shared, frequently updated file store requiring Entra ID integration.

Answer

Azure Blob Storage with a private container.

Answer

Azure NetApp Files.

Answer

Azure Disk Storage with shared disks.

Question 9

You are developing a solution that stores user-uploaded profile pictures. Users upload pictures that are then displayed on their profile page. After 30 days, if the user hasn't logged in, the system moves the picture to cold storage. You need to choose the initial access tier for the container to optimize cost and performance for frequently accessed pictures. Which tier should you use?

Accepted Answer

Hot. The Hot tier is the correct initial access tier because the profile pictures are frequently accessed immediately after upload (e.g., displayed on profile pages). The Hot tier is optimized for high-frequency read/write operations with the lowest latency, making it cost-effective for data that is accessed often. After 30 days of inactivity, the system moves the picture to cold storage, so the initial tier should prioritize performance for active data, not long-term archival cost savings.

Answer

Cool

Answer

Archive

Answer

Premium

Question 10

You are processing messages from an Azure Storage queue in a worker role. To handle messages that repeatedly fail, you want to move them to a separate 'poison' queue after 5 delivery attempts. Which property of the received message should you check to determine the number of attempts?

Accepted Answer

DequeueCount. The DequeueCount property tracks how many times a message has been dequeued from the queue. Each time a worker role retrieves the message but fails to process it (and does not delete it), the message becomes visible again after the visibility timeout expires, incrementing DequeueCount. By checking this property, you can implement a retry policy that moves the message to a poison queue after a threshold (e.g., 5 attempts).

Answer

MessageId

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ExpirationTime

Answer

PopReceipt

Question 11

You store application logs in Azure Blob Storage. The logs are accessed frequently for the first 7 days, then rarely. After 30 days, they must be deleted to minimize cost. Which approach should you use?

Accepted Answer

Configure a lifecycle management policy to tier to cool after 7 days and delete after 30 days. Option C is correct because Azure Blob Storage lifecycle management policies allow you to automatically transition blobs to a cooler tier (cool) after a specified number of days and then delete them after another period, all without manual intervention or additional services. This directly meets the requirement of frequent access for 7 days, rare access afterward, and deletion at 30 days, minimizing cost by leveraging tiered storage and automated rules.

Answer

Manually move blobs to cool tier after 7 days and delete after 30 days using a script

Answer

Use blob snapshots and delete snapshots after 30 days

Answer

Use Azure Data Factory to copy old logs to archive storage and delete original

Question 12

You need to allow a client application to read a specific blob from Azure Blob Storage for one hour, without exposing your storage account key. Which approach should you use?

Accepted Answer

Generate a shared access signature (SAS) URI with read permission and expiry of one hour. Option B is correct because a shared access signature (SAS) URI allows you to delegate limited access (read permission) to a specific blob for a defined time period (one hour) without exposing your storage account key. The SAS token is generated using the account key but does not reveal it, ensuring secure, time-bound access.

Answer

Provide the storage account access key to the client

Answer

Use Azure RBAC to grant the client the Storage Blob Data Reader role for one hour

Answer

Make the blob publicly accessible for one hour using a stored access policy

Question 13

You are developing a solution that stores large media files in Azure Blob Storage. Users access these files frequently for the first 30 days, then rarely afterwards. To optimize costs, you need to automatically move blobs to a cooler tier after 30 days of creation. Which Azure feature should you use?

Accepted Answer

Lifecycle management policies. Azure Blob Storage lifecycle management policies allow you to automatically transition blobs to cooler tiers (e.g., from Hot to Cool) based on age or last modification time. By defining a rule that moves blobs to the Cool tier 30 days after creation, you optimize storage costs for frequently accessed files that become rarely used. This feature is purpose-built for automating tier transitions without manual intervention or custom code.

Answer

Blob inventory

Answer

Change feed

Answer

Immutable storage

Question 14

You need to store small binary blobs (average 50 KB) that are accessed very frequently for a short period, then never accessed again. The total volume is high. Which storage tier is most cost-effective for the initial upload?

Accepted Answer

Hot. The Hot tier is the most cost-effective for the initial upload because it is optimized for frequent access and low latency, and for small blobs (average 50 KB) that are accessed very frequently for a short period, the per-GB storage cost is higher than Cool or Cold, but the access cost (per-operation charges) is significantly lower. Since the blobs are never accessed again after the short period, the high access frequency during that period makes Hot the cheapest option when considering total cost (storage + access operations), as Cool/Cold tiers would incur much higher per-read operation costs that outweigh their lower storage costs.

Answer

Cool

Answer

Cold

Answer