AZ204 (Develop for Azure Storage)

Scenario: You are developing a solution that stores JSON documents in Azure Cosmos DB. You need to ensure strong consistency for all read operations.

Solution: You configure the Cosmos DB account to use Session consistency.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Session consistency is weaker than strong consistency. To guarantee strong consistency, you must explicitly set the consistency level to Strong.

Scenario: You are building an event-driven system that reacts to changes in a Cosmos DB container.

Solution: You implement the Change Feed Processor library in your application.

Does the solution meet the goal?

• Yes

• No

Answer explanation

The Change Feed Processor is the correct way to react to changes in Cosmos DB containers.

You want to store large binary files in Azure and access them via HTTP.

Solution: You use Azure Blob Storage and configure public access to the container.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Blob Storage supports storing large binary files and can be accessed via HTTP if public access is enabled.

You need to automatically delete blobs older than 30 days.

Solution: You implement a background job in your app to delete old blobs.

Does the solution meet the goal?

• Yes

• No

Answer explanation

While this works, the better solution is to use Azure Blob Lifecycle Management, which is built-in and more efficient.

You want to store metadata about each blob, such as the uploader’s name.

Solution: You use blob metadata properties.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Blob metadata is designed for storing custom key-value pairs like uploader names.

You need to ensure that a Cosmos DB container automatically scales throughput based on usage.

Solution: You configure the container with manual throughput.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Manual throughput does not auto-scale. You need to configure autoscale throughput.

You want to ensure that all writes to Cosmos DB are acknowledged only after being committed to multiple regions.

Solution: You set the consistency level to Bounded Staleness.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Only Strong consistency ensures multi-region commit acknowledgment.

You want to trigger an Azure Function whenever a new blob is uploaded.

Solution: You bind the function to a Blob Storage trigger.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Blob triggers are designed for this exact use case.

You want to store structured data with a flexible schema and query it using SQL-like syntax.

Solution: You use Azure Cosmos DB with the SQL API.

Does the solution meet the goal?

• Yes

• No

Answer explanation

Cosmos DB with SQL API supports flexible schemas and SQL-like queries.

You want to store images in Cosmos DB.

Solution: You encode the images in Base64 and store them as strings.

Does the solution meet the goal?

• Yes

• No

Answer explanation

While technically possible, this is inefficient. Use Blob Storage for binary data.