Question 515 of 981
AZ-900 Describe cloud concepts Practice Question
A startup wants to deploy a web application that experiences unpredictable traffic spikes. They need to scale resources automatically without manual intervention. Which benefit of cloud computing directly addresses this requirement?
⚠ Common exam trap
Test-takers frequently confuse elasticity with high availability or fault tolerance, because both involve multiple resources, but elasticity specifically addresses dynamic scaling to meet variable demand, not redundancy or failure recovery.
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
✓
Elasticity
Elasticity is the cloud computing benefit that enables resources to automatically scale out (add instances) during traffic spikes and scale in (remove instances) when demand drops, without manual intervention. This directly matches the startup's need to handle unpredictable traffic patterns by dynamically adjusting compute capacity, typically using services like Azure Virtual Machine Scale Sets or Azure App Service auto-scale rules.
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 is about keeping a service reachable and operational despite failures, typically by distributing workloads across availability zones or regions to achieve high uptime SLAs. Although an HA architecture may include multiple instances behind a load balancer, those instances are usually a fixed count unless a separate scaling policy exists. Thus, HA alone does not automatically adjust capacity to handle unexpected traffic changes.
When this WOULD be correct
A question asks: 'A company needs to ensure its web application remains operational during a regional data center outage. Which benefit of cloud computing addresses this?' High availability would be correct because it focuses on minimizing downtime through redundancy across zones.
- ✓
Elasticity
Why this is correct
Elasticity is the cloud characteristic that allows a web application to automatically increase or decrease compute, storage, or networking resources in response to live traffic. Azure autoscale, often paired with Virtual Machine Scale Sets or App Service, uses metric thresholds such as CPU utilization or request queue length to add or remove instances on demand. This directly addresses unpredictable spikes and troughs, making it the correct answer.
- ✗
Disaster recovery
Why it's wrong here
Disaster recovery is a business continuity strategy for recovering an entire application or data center after catastrophic events such as regional outages, using tools like Azure Site Recovery or geo-replicated storage. Its key metrics are recovery point objective and recovery time objective, which measure acceptable data loss and recovery time, not the dynamic resource scaling needed for variable web traffic. Disaster recovery is a reactive process triggered by a disaster, not a proactive scaling response to demand changes.
When this WOULD be correct
A question asking which cloud benefit ensures business continuity after a major outage or natural disaster, with options including high availability, fault tolerance, and disaster recovery, would make disaster recovery correct.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance goes beyond high availability by enabling a system to continue functioning with zero interruption when a specific component, disk, or server fails, often through active-active redundant hardware. It focuses on masking failures and preserving session continuity, not on reading traffic metrics or provisioning extra capacity. A fault-tolerant deployment can still struggle with a sudden load spike because scaling and fault masking are independent concerns.
When this WOULD be correct
A question asks: 'Which cloud computing benefit ensures that a web application remains operational even if a server fails?' In that context, fault tolerance is correct because it maintains service continuity through redundancy.
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.
✓ElasticityCorrect answer▾
Why this is correct
Elasticity is the cloud characteristic that allows a web application to automatically increase or decrease compute, storage, or networking resources in response to live traffic. Azure autoscale, often paired with Virtual Machine Scale Sets or App Service, uses metric thresholds such as CPU utilization or request queue length to add or remove instances on demand. This directly addresses unpredictable spikes and troughs, making it the correct answer.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures the application remains accessible during failures, but it does not automatically scale resources in response to traffic spikes. The question specifically requires automatic scaling, which is elasticity.
★ When this WOULD be the correct answer
A question asks: 'A company needs to ensure its web application remains operational during a regional data center outage. Which benefit of cloud computing addresses this?' High availability would be correct because it focuses on minimizing downtime through redundancy across zones.
Why candidates choose this
Candidates often confuse high availability with elasticity because both involve handling increased load, but high availability is about uptime and redundancy, not dynamic scaling.
✗Disaster recoveryWrong answer — click to see why▾
Why this is wrong here
Disaster recovery focuses on restoring systems and data after a catastrophic failure, not on automatically scaling resources to handle traffic spikes.
★ When this WOULD be the correct answer
A question asking which cloud benefit ensures business continuity after a major outage or natural disaster, with options including high availability, fault tolerance, and disaster recovery, would make disaster recovery correct.
Why candidates choose this
Candidates may confuse disaster recovery with the ability to handle unexpected events, mistakenly thinking it includes scaling for traffic spikes.
✗Fault toleranceWrong answer — click to see why▾
Why this is wrong here
Fault tolerance ensures system operation during component failures, but does not address automatic scaling to handle traffic spikes. The question specifically requires scaling resources automatically based on demand, which is elasticity.
★ When this WOULD be the correct answer
A question asks: 'Which cloud computing benefit ensures that a web application remains operational even if a server fails?' In that context, fault tolerance is correct because it maintains service continuity through redundancy.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve handling disruptions, but fault tolerance focuses on failure resilience, not dynamic scaling.
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?”
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Last reviewed: Jun 11, 2026
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.
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