AZ-900 Describe Azure architecture and services Practice Question
A US-based financial services company must ensure that all customer data remains within the United States at all times to comply with regulatory requirements. The company plans to replicate its Azure SQL database between two Azure regions for disaster recovery. The solution must guarantee that if a region experiences a major outage, the paired region is prioritized for recovery. Additionally, the solution should ensure that during planned maintenance, only one region in the pair is updated at a time. Which Azure architecture feature should the company use?
⚠ Common exam trap
It's easy for candidates to confuse Availability Zones (which protect against datacenter failures within a single region) with Region Pairs (which protect against full region failures and ensure data residency and sequential maintenance), leading them to select Availability Zones for cross-region disaster recovery scenarios.
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
✓
Region Pairs
Region Pairs are the correct choice because Azure guarantees that each region is paired with another region within the same geography (e.g., East US with West US) to provide physical isolation, prioritized disaster recovery, and sequential planned maintenance updates. This ensures that during an outage, recovery is directed to the paired region, and during maintenance, only one region in the pair is updated at a time, meeting the company's regulatory and availability requirements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Availability Zones
Why it's wrong here
Availability Zones are physically separate datacenters within a single Azure region. They do not span across two different regions and therefore cannot provide disaster recovery across regions or ensure data remains within a specific geography like the United States.
When this WOULD be correct
A company needs high availability for an application within a single Azure region, requiring protection against datacenter-level failures. The solution must deploy VMs across multiple physical locations with independent power and networking within that region.
- ✓
Region Pairs
Why this is correct
Azure region pairs are two Azure regions within the same geography (e.g., East US and West US) that are paired by Microsoft. They offer prioritized disaster recovery (one region is automatically prioritized for recovery) and sequential updates (only one region in the pair is updated during planned maintenance), making them the correct choice.
- ✗
Resource Groups
Why it's wrong here
Resource Groups are logical containers in Azure used to organize and manage related resources, such as grouping a virtual network and its VMs for lifecycle management. They provide no inherent disaster recovery capability, no maintenance sequencing, and no built-in replication across distinct geographic regions. A resource group simply holds resources that may be deployed to a single region, meaning it does not satisfy the requirement of being located within the same geography for recovery purposes.
When this WOULD be correct
A company needs to organize all resources for a specific project (e.g., a web app, database, and storage) under a single management unit for RBAC, tagging, and cost tracking. Resource Groups would be the correct answer.
- ✗
Azure Policy
Why it's wrong here
Azure Policy is an Azure governance service that evaluates and enforces compliance rules on resources (e.g., restricting resource SKUs or locations) by applying policy definitions to management groups, subscriptions, or resource groups. It is fundamentally a control-plane tool for auditing and remediation, not an infrastructure topology feature. Azure Policy cannot influence how regions are paired, which region gets prioritized for disaster recovery, or how platform updates are sequenced—those are physical and operational characteristics of Azure's region-pair architecture.
When this WOULD be correct
A company needs to ensure that all Azure resources in a subscription are deployed only in the US regions to meet regulatory requirements. Azure Policy with a built-in policy 'Allowed locations' would enforce this constraint at the subscription or resource group level.
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.
✓Region PairsCorrect answer▾
Why this is correct
Azure region pairs are two Azure regions within the same geography (e.g., East US and West US) that are paired by Microsoft. They offer prioritized disaster recovery (one region is automatically prioritized for recovery) and sequential updates (only one region in the pair is updated during planned maintenance), making them the correct choice.
✗Availability ZonesWrong answer — click to see why▾
Why this is wrong here
Availability Zones protect against datacenter failures within a single region, not across regions. The question requires cross-region disaster recovery with data residency in the US, which Availability Zones cannot provide.
★ When this WOULD be the correct answer
A company needs high availability for an application within a single Azure region, requiring protection against datacenter-level failures. The solution must deploy VMs across multiple physical locations with independent power and networking within that region.
Why candidates choose this
Candidates may confuse Availability Zones with region pairs because both involve redundancy, but zones are intra-region while pairs are inter-region, and the question explicitly mentions two Azure regions.
✗Resource GroupsWrong answer — click to see why▾
Why this is wrong here
Resource Groups are logical containers for managing Azure resources, but they do not provide geo-replication, disaster recovery prioritization, or coordinated maintenance across regions. They cannot enforce data residency or control region pairing.
★ When this WOULD be the correct answer
A company needs to organize all resources for a specific project (e.g., a web app, database, and storage) under a single management unit for RBAC, tagging, and cost tracking. Resource Groups would be the correct answer.
Why candidates choose this
Candidates may confuse Resource Groups with region-level features or think they can group resources across regions to manage compliance, but Resource Groups have no geographic or replication capabilities.
✗Azure PolicyWrong answer — click to see why▾
Why this is wrong here
Azure Policy is used to enforce compliance rules on Azure resources (e.g., requiring a specific tag or location), but it does not control disaster recovery replication, region pairing, or maintenance sequencing for Azure SQL databases.
★ When this WOULD be the correct answer
A company needs to ensure that all Azure resources in a subscription are deployed only in the US regions to meet regulatory requirements. Azure Policy with a built-in policy 'Allowed locations' would enforce this constraint at the subscription or resource group level.
Why candidates choose this
Candidates may confuse regulatory compliance enforcement (Azure Policy) with the architectural feature that ensures data residency during disaster recovery (Region Pairs), as both involve 'compliance' and 'regions'.
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
Region
A region is a distinct geographic location where a cloud provider operates multiple data centers that are connected by low-latency networks and provide cloud services.
Key term
Availability
Availability is the measure of how often a system or service is operational and accessible when needed, typically expressed as a percentage of uptime.
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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.