Question 564 of 1,031

Describe cloud concepts →mediumMultiple ChoiceObjective-mapped

AZ-900 Describe cloud concepts Practice Question

This AZ-900 practice question tests your understanding of describe cloud concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company hosts a web application on a single Azure virtual machine. Over the past month, the application's CPU utilization has consistently remained above 90%, causing slow response times. The administrator plans to modify the virtual machine's size from Standard_D2s_v3 (2 vCPUs) to Standard_D8s_v3 (8 vCPUs) to improve performance. Which scaling method does this change represent?

Question 1mediummultiple choice

Full question →

A
Horizontal scaling (scaling out)
Why wrong: Horizontal scaling involves adding more instances (e.g., increasing the number of VMs), not increasing the capacity of a single instance. This option is incorrect because the administrator is resizing an existing VM, not adding additional VMs.
B
Vertical scaling (scaling up)
Vertical scaling (or scaling up/down) refers to increasing or decreasing the resources (CPU, memory, etc.) of a single virtual machine or resource. This change increases the CPU capacity of the existing VM, which is a classic example of scaling up.
C
Elastic scaling
Why wrong: Elastic scaling is a characteristic of cloud computing where resources automatically scale in and out based on demand, but it is not a specific method of scaling like vertical or horizontal. The scenario describes a manual change, not an automatic adjustment.
D
Auto-scaling
Why wrong: Auto-scaling is a feature that automatically adjusts resources (either horizontally or vertically) based on predefined rules or metrics. This scenario describes a manual manual resizing, not an automated action, so auto-scaling does not apply.

Full breakdown with real-world context →

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

✓

Vertical scaling (scaling up)

Vertical scaling (scaling up) increases the power of an existing resource by upgrading its size or capacity. In this scenario, changing the virtual machine from Standard_D2s_v3 (2 vCPUs) to Standard_D8s_v3 (8 vCPUs) adds more CPU cores to the same VM, which is a classic example of scaling up. This approach improves performance without adding additional VM instances.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Horizontal scaling (scaling out)
Why it's wrong here
Horizontal scaling involves adding more instances (e.g., increasing the number of VMs), not increasing the capacity of a single instance. This option is incorrect because the administrator is resizing an existing VM, not adding additional VMs.
✓
Vertical scaling (scaling up)
Why this is correct
Vertical scaling (or scaling up/down) refers to increasing or decreasing the resources (CPU, memory, etc.) of a single virtual machine or resource. This change increases the CPU capacity of the existing VM, which is a classic example of scaling up.
Related concept
Read the scenario before looking for a memorised answer.
✗
Elastic scaling
Why it's wrong here
Elastic scaling is a characteristic of cloud computing where resources automatically scale in and out based on demand, but it is not a specific method of scaling like vertical or horizontal. The scenario describes a manual change, not an automatic adjustment.
✗
Auto-scaling
Why it's wrong here
Auto-scaling is a feature that automatically adjusts resources (either horizontally or vertically) based on predefined rules or metrics. This scenario describes a manual manual resizing, not an automated action, so auto-scaling does not apply.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often confuse vertical scaling (changing the size of a single resource) with horizontal scaling (adding more resources), especially when the question describes a performance issue that could be solved by either method, but the specific action of changing the VM size clearly indicates vertical scaling.

Trap categories for this question

Scenario analysis trap
Elastic scaling is a characteristic of cloud computing where resources automatically scale in and out based on demand, but it is not a specific method of scaling like vertical or horizontal. The scenario describes a manual change, not an automatic adjustment.

Detailed technical explanation

How to think about this question

Azure virtual machine sizes are grouped into families (e.g., D-series for general-purpose workloads) with specific vCPU-to-memory ratios. The Standard_D8s_v3 offers 8 vCPUs and 32 GB of RAM, compared to the Standard_D2s_v3's 2 vCPUs and 8 GB of RAM. Under the hood, resizing a VM triggers a reboot and may move the VM to a different host cluster if the target size is not available in the current cluster, which can cause a brief downtime. This is distinct from horizontal scaling, which typically requires a load balancer to distribute traffic across multiple instances.

KKey Concepts to Remember

Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.

TExam Day Tips

Watch for words such as best, first, most likely and least administrative effort.
Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this AZ-900 question test?

Describe cloud concepts — This question tests Describe cloud concepts — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Vertical scaling (scaling up) — Vertical scaling (scaling up) increases the power of an existing resource by upgrading its size or capacity. In this scenario, changing the virtual machine from Standard_D2s_v3 (2 vCPUs) to Standard_D8s_v3 (8 vCPUs) adds more CPU cores to the same VM, which is a classic example of scaling up. This approach improves performance without adding additional VM instances.

What should I do if I get this AZ-900 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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