Protect VMs from Datacenter Failure with Availability Zones
A line-of-business app runs on two VMs in an Azure region that supports availability zones. The business wants protection from a datacenter failure and wants the VMs placed in different physical locations within the region. Which deployment choice should be used?
Quick Answer
The answer is to deploy the two VMs across two availability zones, placing one VM in each zone. This is correct because availability zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking, so if one datacenter fails, the other VM remains available. On the AZ-104 exam, this scenario tests your understanding of high-availability architecture versus fault domains or availability sets, which protect against rack-level failures but not entire datacenter outages. A common trap is confusing availability zones with availability sets—remember that zones protect against datacenter failure, while sets protect against hardware failure within a single datacenter. For a quick memory tip, think “zones stop zone-down, sets stop server-down.”
⚠ Common exam trap
A common mix-up: candidates confuse availability sets (which protect against rack failures) with availability zones (which protect against datacenter failures), leading them to choose an availability set when the question explicitly requires different physical locations within the region.
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
✓
Two availability zones with one VM in each zone
Availability zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking. Placing one VM in each of two zones ensures that if one datacenter fails, the other VM remains available. This directly meets the requirement for protection from a datacenter failure with VMs in different physical locations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
An availability set with two fault domains
Why it's wrong here
An availability set protects against host and maintenance events, but not against a full zone outage.
When this WOULD be correct
If the question asked for protection against hardware failures within a single datacenter (e.g., server rack or network switch failure) and required high availability for VMs in the same datacenter, an availability set with multiple fault domains would be correct.
- ✓
Two availability zones with one VM in each zone
Why this is correct
Availability zones place resources in separate physical datacenters within a region, improving resilience to zone failure.
- ✗
A proximity placement group for both VMs
Why it's wrong here
A proximity placement group reduces latency between resources, but it does not provide disaster resilience.
When this WOULD be correct
A proximity placement group would be correct if the question required minimizing network latency between VMs for a tightly coupled workload, such as a high-performance computing application, without concern for datacenter-level failure.
- ✗
A single larger VM size with Premium SSD
Why it's wrong here
Increasing size can improve capacity, but one VM still remains a single point of failure.
When this WOULD be correct
This option would be correct in a scenario where the requirement is to maximize performance for a single VM running a critical application, with no need for high availability across datacenters, and the budget allows for a larger VM and premium storage.
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-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓Two availability zones with one VM in each zoneCorrect answer▾
Why this is correct
Availability zones place resources in separate physical datacenters within a region, improving resilience to zone failure.
✗An availability set with two fault domainsWrong answer — click to see why▾
Why this is wrong here
An availability set with two fault domains protects against rack-level failures within a single datacenter, not against a full datacenter failure. The question requires physical separation across different datacenters, which only availability zones provide.
★ When this WOULD be the correct answer
If the question asked for protection against hardware failures within a single datacenter (e.g., server rack or network switch failure) and required high availability for VMs in the same datacenter, an availability set with multiple fault domains would be correct.
Why candidates choose this
Candidates may confuse fault domains with availability zones, thinking that multiple fault domains provide datacenter-level redundancy, when in fact they only distribute VMs across different racks within one datacenter.
✗A proximity placement group for both VMsWrong answer — click to see why▾
Why this is wrong here
A proximity placement group reduces network latency by co-locating VMs, but it does not protect against datacenter failure because VMs can still be placed in the same datacenter or fault domain.
★ When this WOULD be the correct answer
A proximity placement group would be correct if the question required minimizing network latency between VMs for a tightly coupled workload, such as a high-performance computing application, without concern for datacenter-level failure.
Why candidates choose this
Candidates may confuse proximity placement groups with high availability features, thinking that grouping VMs together provides redundancy, or they may overlook the specific requirement for protection from a datacenter failure.
✗A single larger VM size with Premium SSDWrong answer — click to see why▾
Why this is wrong here
A single larger VM with Premium SSD does not provide protection from a datacenter failure because it is a single VM that can still be affected by a datacenter outage, regardless of its size or disk type.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the requirement is to maximize performance for a single VM running a critical application, with no need for high availability across datacenters, and the budget allows for a larger VM and premium storage.
Why candidates choose this
Candidates may think that a larger, more powerful VM with faster storage inherently provides better reliability, confusing performance enhancements with fault tolerance.
Analysis generated from the official AZ-104blueprint 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
Managed Identities for Azure Resources
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.
About these practice questions
One of 1,049 original AZ-104 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on AZ-104
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Based on the exhibit, a workload must remain available even if one datacenter in an Azure region becomes unavailable. The region supports zone deployment. What should the administrator configure?
easy- A.An availability set.
- ✓ B.Availability zones.
- C.A resource lock.
- D.A user-defined route.
Why B: Availability zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking. Deploying the workload across two or more zones ensures that if one datacenter fails, the other zones continue to operate, maintaining availability. This directly meets the requirement of surviving a single datacenter outage within a region that supports zone deployment.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 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-104 exam.