AZ-900 Describe Azure architecture and services Practice Question
A company runs an on-premises line-of-business application that uses a SQL Server database. The database currently has 500 GB of data and is accessed by 50 users simultaneously. The company is planning to migrate this database to Azure. The IT team wants to minimize administrative overhead for patching the operating system and database engine, and for performing automated backups with point-in-time restore. The team also wants the ability to scale compute and storage independently without managing virtual machines. Which Azure service should they choose?
⚠ Common exam trap
A common mix-up: candidates confuse the managed IaaS option (SQL Server on Azure VM) with PaaS, thinking it also automates patching and backups, but in reality, IaaS leaves all OS and DB engine maintenance to the customer.
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 SQL Database (Platform-as-a-Service)
Azure SQL Database is a Platform-as-a-Service (PaaS) offering that fully manages the underlying operating system and SQL Server engine, including patching and updates. It provides automated backups with point-in-time restore (up to 35 days retention) and allows independent scaling of compute (DTUs/vCores) and storage without any virtual machine management. This directly meets the team's requirements to minimize administrative overhead while supporting 500 GB of data and 50 concurrent users.
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 (Platform-as-a-Service)
Why this is correct
Azure SQL Database is a fully managed Platform-as-a-Service (PaaS) relational database built on Microsoft SQL Server technology, providing automatic OS updates, SQL engine patching, and backup management as core services. It offers a 99.99% availability SLA with built-in high availability, and supports independent scaling of compute and storage without requiring the customer to manage any virtual machines or underlying infrastructure. Because it exposes a T-SQL surface, it is the appropriate PaaS choice for a SQL Server line-of-business application, directly meeting the requirement to reduce management overhead.
- ✗
SQL Server on Azure Virtual Machine (Infrastructure-as-a-Service)
Why it's wrong here
Incorrect. SQL Server on an Azure VM (IaaS) requires the customer to manage the operating system, SQL Server patching, and backup configuration. While possible, it increases administrative overhead and does not align with the goal of minimizing management tasks.
When this WOULD be correct
A company needs full control over the SQL Server configuration (e.g., custom instance settings, specific SQL Server version, or third-party agents) and is willing to manage patching, backups, and VM scaling themselves.
- ✗
Azure Cosmos DB
Why it's wrong here
Incorrect. Azure Cosmos DB is a globally distributed NoSQL database service. It supports multiple APIs (e.g., SQL API, MongoDB) but is not a relational database and does not support the same SQL Server Transact-SQL (T-SQL) features that the existing application likely depends on. The scenario specifies a SQL Server database.
When this WOULD be correct
A company needs a globally distributed, multi-model database for a new application with high throughput and low latency, requiring flexible schema and automatic scaling across regions. They do not need SQL Server compatibility or point-in-time restore for a relational database.
- ✗
Azure Database for MySQL
Why it's wrong here
Incorrect. Azure Database for MySQL is a fully managed MySQL database service, but the existing application uses SQL Server. Migrating to a different database engine would require significant application changes, and the scenario does not indicate such a need.
When this WOULD be correct
A company runs a MySQL-based application on-premises and wants to migrate to Azure with minimal administrative overhead for patching, automated backups, and independent scaling of compute and storage. They do not need SQL Server compatibility.
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 SQL Database (Platform-as-a-Service)Correct answer▾
Why this is correct
Azure SQL Database is a fully managed Platform-as-a-Service (PaaS) relational database built on Microsoft SQL Server technology, providing automatic OS updates, SQL engine patching, and backup management as core services. It offers a 99.99% availability SLA with built-in high availability, and supports independent scaling of compute and storage without requiring the customer to manage any virtual machines or underlying infrastructure. Because it exposes a T-SQL surface, it is the appropriate PaaS choice for a SQL Server line-of-business application, directly meeting the requirement to reduce management overhead.
✗SQL Server on Azure Virtual Machine (Infrastructure-as-a-Service)Wrong answer — click to see why▾
Why this is wrong here
SQL Server on Azure VM requires managing OS and SQL Server patching, backups, and VM scaling, which contradicts the requirement to minimize administrative overhead and avoid managing virtual machines.
★ When this WOULD be the correct answer
A company needs full control over the SQL Server configuration (e.g., custom instance settings, specific SQL Server version, or third-party agents) and is willing to manage patching, backups, and VM scaling themselves.
Why candidates choose this
Candidates may think that migrating a SQL Server database to Azure requires a VM to maintain compatibility, not realizing that Azure SQL Database provides near-complete compatibility with reduced management.
✗Azure Cosmos DBWrong answer — click to see why▾
Why this is wrong here
Azure Cosmos DB is a NoSQL database service, not a SQL Server relational database. The question specifies a SQL Server database with 500 GB of data and 50 concurrent users, requiring SQL Server compatibility and point-in-time restore, which Cosmos DB does not provide.
★ When this WOULD be the correct answer
A company needs a globally distributed, multi-model database for a new application with high throughput and low latency, requiring flexible schema and automatic scaling across regions. They do not need SQL Server compatibility or point-in-time restore for a relational database.
Why candidates choose this
Candidates may confuse Azure Cosmos DB as a general-purpose database service that can replace SQL Server, overlooking that it is NoSQL and lacks SQL Server-specific features like T-SQL and automated backups with point-in-time restore for relational workloads.
✗Azure Database for MySQLWrong answer — click to see why▾
Why this is wrong here
The question specifies a SQL Server database, and Azure Database for MySQL is a different database engine (MySQL), not SQL Server. It also does not support the same point-in-time restore and independent scaling features as Azure SQL Database for SQL Server workloads.
★ When this WOULD be the correct answer
A company runs a MySQL-based application on-premises and wants to migrate to Azure with minimal administrative overhead for patching, automated backups, and independent scaling of compute and storage. They do not need SQL Server compatibility.
Why candidates choose this
Candidates may confuse Azure Database for MySQL with Azure SQL Database, thinking both are managed database services, and overlook the specific requirement for SQL Server database engine compatibility.
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?”
Go deeper
Related to this question
Learn chapter
Azure Regions and Geographies
Key term
Azure SQL Database
Azure SQL Database is a fully managed relational database-as-a-service (DBaaS) in Microsoft Azure, based on the SQL Server engine, that handles scaling, backups, patching, and high availability automatically.
Key term
PaaS
Platform as a Service (PaaS) is a cloud computing model that provides a managed platform for developers to build, run, and manage applications without dealing with the underlying infrastructure.
About these practice questions
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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.