AZ-900 Describe cloud concepts Practice Question
A company runs a critical transaction processing application on two Azure virtual machines. The infrastructure is designed so that if one virtual machine encounters a hardware failure and stops functioning, the other virtual machine continues to serve traffic without any interruption or loss of service. Which cloud computing characteristic does this design primarily address?
⚠ Common exam trap
Many exam-takers confuse high availability with fault tolerance, but high availability allows for brief downtime during failover, while fault tolerance guarantees zero interruption, which is the key distinction tested in this question.
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
✓
Fault tolerance
The design ensures that if one virtual machine fails due to a hardware failure, the other continues serving traffic without any interruption or loss of service. This is the definition of fault tolerance, which eliminates any single point of failure and maintains continuous operation even when a component fails. High availability reduces downtime but may allow brief interruptions during failover, whereas fault tolerance guarantees zero interruption.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
High availability
Why it's wrong here
High availability refers to ensuring a system remains operational for a high percentage of time, often through redundancy and failover. However, it typically allows for a brief interruption during failover. The scenario states 'without any interruption', which aligns more closely with fault tolerance.
When this WOULD be correct
A question describing a design where two VMs in an availability set ensure at least one VM is running after planned or unplanned maintenance, but brief interruptions (e.g., during failover) are acceptable, would make high availability the correct answer.
- ✓
Fault tolerance
Why this is correct
Correct. Fault tolerance is the ability of a system to continue operating without interruption even when one or more components fail. The design where a failure of one VM causes no service disruption is a classic example of fault tolerance.
- ✗
Disaster recovery
Why it's wrong here
Disaster recovery (DR) is concerned with restoring systems and data after a catastrophic event that disrupts an entire site, such as a datacenter or region failure. The scenario involves a single VM failure within the same region, which is a localized hardware or software fault, not a disaster. A DR plan would include backups, replication to a secondary region, and defined RPO/RTO goals—none of which are implied here. Because the system continues operating without interruption for any component failure, it is not a recovery process but an immediate resilience mechanism.
When this WOULD be correct
A question describing a scenario where a company needs to recover its critical application after a regional outage, with data backups and failover to a secondary Azure region, would make disaster recovery the correct answer.
- ✗
Scalability
Why it's wrong here
Scalability is about a system's ability to handle increased load by adding resources (scale up/out) or reducing them to match demand. The described design—two VMs with automatic failover for a single VM failure—does not add processing capacity or throughput; it only preserves existing capacity during a component failure. Since no aspect of the architecture adjusts to varying workloads, it has no bearing on scalability. Even if the VMs are load-balanced, the primary intent is resilience, not elastic or predictable capacity expansion.
When this WOULD be correct
A question asking: 'A web application experiences sudden traffic spikes. The company wants to automatically add more virtual machines during peak times and remove them when demand drops. Which cloud characteristic does this address?' would make scalability correct.
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.
✓Fault toleranceCorrect answer▾
Why this is correct
Correct. Fault tolerance is the ability of a system to continue operating without interruption even when one or more components fail. The design where a failure of one VM causes no service disruption is a classic example of fault tolerance.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures minimal downtime through redundancy, but the question specifies 'without any interruption or loss of service,' which is fault tolerance—the ability to continue operating despite failures without any impact.
★ When this WOULD be the correct answer
A question describing a design where two VMs in an availability set ensure at least one VM is running after planned or unplanned maintenance, but brief interruptions (e.g., during failover) are acceptable, would make high availability the correct answer.
Why candidates choose this
Candidates often confuse high availability with fault tolerance because both involve redundancy; however, high availability allows for brief downtime during failover, while fault tolerance requires zero interruption.
✗Disaster recoveryWrong answer — click to see why▾
Why this is wrong here
Disaster recovery focuses on restoring services after a major outage, often in a different region, not on maintaining continuous operation during a hardware failure within the same region.
★ When this WOULD be the correct answer
A question describing a scenario where a company needs to recover its critical application after a regional outage, with data backups and failover to a secondary Azure region, would make disaster recovery the correct answer.
Why candidates choose this
Candidates may confuse fault tolerance (immediate failover) with disaster recovery (planned recovery after a disaster), as both involve redundancy and failover mechanisms.
✗ScalabilityWrong answer — click to see why▾
Why this is wrong here
Scalability refers to the ability to handle increased load by adding resources, not to maintaining service during hardware failures. The scenario describes fault tolerance, not scalability.
★ When this WOULD be the correct answer
A question asking: 'A web application experiences sudden traffic spikes. The company wants to automatically add more virtual machines during peak times and remove them when demand drops. Which cloud characteristic does this address?' would make scalability correct.
Why candidates choose this
Candidates may confuse the ability to handle failures with the ability to handle increased load, or think that having multiple VMs inherently provides scalability.
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
What is Cloud Computing?
Key term
Cloud computing
Cloud computing is the on-demand delivery of IT resources over the internet, allowing users to access computing power, storage, and applications without owning physical hardware.
Key term
High availability
High availability is a system design approach that aims to keep applications and services operational and accessible with minimal downtime, even when some components fail.
About these practice questions
This AZ-900 question is part of Courseiva's 981-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam 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.