AZ-900 Describe Azure architecture and services Practice Question
A web application needs to store large amounts of unstructured data (images, documents) that will be accessed via HTTP from anywhere in the world. The data must be highly durable and scalable. Which Azure storage solution is most appropriate?
⚠ Common exam trap
Test-takers frequently confuse Azure File Storage (a managed SMB share) with Blob Storage, not realizing that File Storage is designed for network file sharing (SMB protocol) rather than HTTP-based global access for unstructured data.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Blob Storage
Azure Blob Storage is designed for storing massive amounts of unstructured data, such as images and documents, and provides HTTP/HTTPS access from anywhere. It offers high durability (99.9999999999% with RA-GRS) and massive scalability, making it the ideal choice for globally accessible, unstructured data workloads.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a relational database engine built on SQL Server, designed for structured data with predefined schemas, relationships, and ACID transactions. Storing large unstructured objects would require embedding BLOBs into table columns or referencing external files, adding schema overhead and constraints that limit scalability and direct HTTP/S accessibility. It is not a substitute for dedicated object storage.
When this WOULD be correct
For a scenario requiring a fully managed relational database with built-in high availability, automatic backups, and support for structured transactional data (e.g., an e-commerce application's customer orders and inventory), Azure SQL Database would be the correct choice.
- ✓
Azure Blob Storage
Why this is correct
Azure Blob Storage is purpose-built object storage for massive amounts of unstructured data, such as images, videos, logs, and backups, that does not conform to a relational schema. It exposes data via HTTP/S using a REST API, enabling direct access from web applications and CDN integration. It offers high durability, redundancy options, and tiered storage to optimize cost.
- ✗
Azure File Storage
Why it's wrong here
Azure File Storage provides fully managed SMB (Server Message Block) file shares that require mounting over the network, making it suitable for lift-and-shift migrations of on-premises file servers and access from virtual machines. It maintains a hierarchical directory structure and file-level locking, which fundamentally differs from object storage semantics and is not designed for direct HTTP/S-based access to large unstructured blobs.
- ✗
Azure Cosmos DB
Why it's wrong here
Azure Cosmos DB is a NoSQL multi-model database supporting key-value, document, graph, and columnar APIs, optimized for globally distributed, low-latency reads and writes on structured or semi-structured JSON-like data. While it can technically store strings as documents, it is not designed for high-throughput binary storage or static unstructured files, and its request-charge pricing model makes it cost-prohibitive for large blobs.
When this WOULD be correct
A question requiring a globally distributed, multi-model database with low-latency access for structured or semi-structured data (e.g., JSON documents) that needs to support real-time applications with flexible schemas and guaranteed throughput.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Azure Blob StorageCorrect answer▾
Why this is correct
Azure Blob Storage is purpose-built object storage for massive amounts of unstructured data, such as images, videos, logs, and backups, that does not conform to a relational schema. It exposes data via HTTP/S using a REST API, enabling direct access from web applications and CDN integration. It offers high durability, redundancy options, and tiered storage to optimize cost.
✗Azure SQL DatabaseWrong answer — click to see why▾
Why this is wrong here
Azure SQL Database is a relational database for structured data, not designed for storing large unstructured files like images and documents. It lacks native HTTP access for blob storage and is not optimized for high-scale unstructured data.
★ When this WOULD be the correct answer
For a scenario requiring a fully managed relational database with built-in high availability, automatic backups, and support for structured transactional data (e.g., an e-commerce application's customer orders and inventory), Azure SQL Database would be the correct choice.
Why candidates choose this
Candidates may confuse 'database' with any data storage, or assume SQL Database can handle unstructured data via BLOB columns, overlooking that Azure Blob Storage is purpose-built for such workloads.
✗Azure Cosmos DBWrong answer — click to see why▾
Why this is wrong here
Azure Cosmos DB is a NoSQL database optimized for low-latency, globally distributed transactional workloads, not for storing large unstructured blobs like images and documents. It is not designed for high-volume blob storage with HTTP access.
★ When this WOULD be the correct answer
A question requiring a globally distributed, multi-model database with low-latency access for structured or semi-structured data (e.g., JSON documents) that needs to support real-time applications with flexible schemas and guaranteed throughput.
Why candidates choose this
Candidates may confuse Cosmos DB's support for unstructured data (e.g., JSON) with blob storage, or think its global distribution and HTTP API make it suitable for storing large files, overlooking its focus on transactional data and higher cost per GB.
Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Azure Regions and Geographies
Key term
Azure Storage
Azure Storage is Microsoft's cloud-based service for storing data like files, messages, and backups with high durability and scalability.
Key term
Blob
A blob is a large piece of unstructured data, like a photo or video, stored in the cloud with a unique identifier.
About these practice questions
Courseiva writes every AZ-900 question from scratch — 981 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.