AZ-900 Describe cloud concepts Practice Question
A retail company hosts an e-commerce website on on-premises servers. During seasonal sales events, the website experiences traffic spikes that last for a few hours. Several years ago, the company purchased additional servers to handle these spikes, but those servers now sit idle for most of the year. The company is considering moving the website to Azure. Which benefit of cloud computing would most directly help the company avoid maintaining idle hardware while still being able to handle traffic spikes?
⚠ Common exam trap
It's easy for candidates to confuse elasticity with high availability, but high availability ensures uptime during failures, not the ability to dynamically adjust capacity to match variable demand.
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 correct answer because it allows the company to automatically scale computing resources up during traffic spikes and scale down when demand drops, eliminating the need to maintain idle on-premises servers. In Azure, this is achieved through features like Virtual Machine Scale Sets and autoscale rules that adjust capacity based on metrics such as CPU usage or request count, ensuring the company only pays for resources consumed during peak periods.
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 (HA) ensures that a service remains operational and accessible with minimal downtime, typically through redundant components, load balancing, and automatic failover mechanisms. HA architectures are designed to mask failures and maintain a certain uptime percentage (e.g., 99.99%), but they do not automatically add or remove resources in response to changes in user demand. While HA contributes to resilience, it does not provide the elastic scaling needed to absorb sudden traffic spikes on an e-commerce website.
When this WOULD be correct
A question asking: 'A company requires its critical application to remain accessible even if a single Azure region experiences an outage. Which benefit of cloud computing should they prioritize?' would make high availability the correct answer.
- ✓
Elasticity
Why this is correct
Elasticity is the ability of a cloud service to automatically increase or decrease the resources allocated to a workload based on real-time demand. This allows the company to handle traffic spikes without maintaining permanently provisioned hardware, and to pay only for what is used.
- ✗
Disaster recovery
Why it's wrong here
Disaster recovery (DR) is a set of policies, tools, and procedures for restoring critical systems and data after a disruptive event such as a natural disaster, cyberattack, or hardware failure. DR focuses on recovery time objective (RTO) and recovery point objective (RPO), leveraging backups, replication, and failover to a secondary site. It does not dynamically adjust compute or storage capacity based on real-time traffic fluctuations, so it cannot solve the need to scale an e-commerce platform to handle peak demand.
When this WOULD be correct
A company wants to ensure its critical applications can be quickly restored after a regional outage, with minimal data loss and downtime. The question would ask about the benefit that provides backup and recovery capabilities across different geographic locations.
- ✗
Geo-redundancy
Why it's wrong here
Geo-redundancy is a data replication feature that copies data to a secondary Azure region for durability and disaster recovery. It does not provide the ability to scale compute or application resources in response to traffic changes.
When this WOULD be correct
A company requires its application to remain available during a regional outage. The question asks which feature ensures data and services are replicated across multiple Azure regions to provide failover capability. Geo-redundancy would be the correct answer.
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 ability of a cloud service to automatically increase or decrease the resources allocated to a workload based on real-time demand. This allows the company to handle traffic spikes without maintaining permanently provisioned hardware, and to pay only for what is used.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures the website remains operational during failures, but it does not address the need to dynamically scale resources up and down to match traffic spikes, which is the core issue of avoiding idle hardware.
★ When this WOULD be the correct answer
A question asking: 'A company requires its critical application to remain accessible even if a single Azure region experiences an outage. Which benefit of cloud computing should they prioritize?' would make high availability the correct answer.
Why candidates choose this
Candidates may confuse high availability with the ability to handle increased load, not realizing that high availability focuses on uptime and redundancy rather than dynamic scaling.
✗Disaster recoveryWrong answer — click to see why▾
Why this is wrong here
Disaster recovery focuses on restoring IT infrastructure and data after a disruptive event, not on dynamically scaling resources to match variable traffic loads.
★ When this WOULD be the correct answer
A company wants to ensure its critical applications can be quickly restored after a regional outage, with minimal data loss and downtime. The question would ask about the benefit that provides backup and recovery capabilities across different geographic locations.
Why candidates choose this
Candidates may confuse disaster recovery with the ability to handle traffic spikes, thinking that having backup servers in a disaster recovery site could also be used to absorb extra load during peak times.
✗Geo-redundancyWrong answer — click to see why▾
Why this is wrong here
Geo-redundancy replicates data across geographically separate data centers for disaster recovery, not for handling short-term traffic spikes. It does not address the need to scale resources up and down dynamically to match demand.
★ When this WOULD be the correct answer
A company requires its application to remain available during a regional outage. The question asks which feature ensures data and services are replicated across multiple Azure regions to provide failover capability. Geo-redundancy would be the correct answer.
Why candidates choose this
Candidates may confuse geo-redundancy with the ability to distribute traffic across regions to handle load spikes, but geo-redundancy is primarily for disaster recovery and high availability, not for elastic 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?”
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
Elasticity
Elasticity is the ability of a cloud system to automatically add or remove computing resources (like servers, storage, or bandwidth) in response to real-time changes in demand.
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.
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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.