AZ-104 Implement and Manage Storage Practice Question
Before changing a managed data disk attached to a VM, you want a point-in-time copy that can be restored later if the change fails. What should you create?
⚠ Common exam trap
A common mix-up: candidates confuse a snapshot with an image, thinking both serve the same purpose, but an image is used for deployment and includes OS configuration, while a snapshot is a raw disk copy for recovery without any generalization.
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
✓
Managed disk snapshot
A managed disk snapshot is a point-in-time, read-only copy of a managed disk that can be used to restore the disk to that exact state if a change fails. Snapshots are incremental, capturing only the changes since the last snapshot, and they exist independently of the source disk, allowing you to create a new disk from the snapshot for recovery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Managed disk snapshot
Why this is correct
A managed disk snapshot is a read-only, full point-in-time copy of a managed disk that can be taken while the VM remains running. It preserves the exact block-level state of the disk, allowing you to restore the disk to its pre-change state or create a new disk from the snapshot. Because it directly captures the disk's data without requiring downtime or generalization, it is the appropriate artifact for protecting the disk before altering it.
- ✗
Availability set
Why it's wrong here
An availability set is a logical grouping of VMs that Azure distributes across fault domains and update domains to guarantee the 99.95% VM uptime SLA for multi-instance deployments. It only affects VM placement and redundancy at the infrastructure level, and it has no mechanism to read, copy, or restore the data stored on a managed disk. While it enhances overall VM availability, it is entirely unrelated to capturing a disk's contents before a configuration change.
When this WOULD be correct
When the question asks for a feature that ensures VM redundancy during planned or unplanned maintenance, such as 'You need to deploy two VMs that are placed on different physical hardware to protect against rack failures. What should you create?'
- ✗
Image
Why it's wrong here
An image is a generalized VM configuration that includes the operating system, data disks, and applications, and is used as a template to create new, cloned VMs. Creating an image from a source disk requires running Sysprep (for Windows) or waagent -deprovision (for Linux), which generalizes the system and strips machine-specific settings—an unsuitable transformation for preserving a point-in-time disk checkpoint. Images serve mass provisioning, not rollback or restoration of a single disk's current state, so they are not used for one-time pre-change backups.
When this WOULD be correct
When you need to create multiple identical VMs from a generalized source, such as deploying a fleet of web servers from a custom OS configuration.
- ✗
Resource lock
Why it's wrong here
A resource lock is an Azure access-control mechanism that prevents unauthorized deletion or modification at a subscription, resource group, or resource level, but it does not generate a restorable copy of the disk's data. In fact, if a lock is applied to the managed disk itself, it would block the very operation you intend to perform, making it counterproductive for a disk-change scenario. Its purpose is governance and protection against accidental changes, not disaster recovery or point-in-time data capture, so it cannot substitute for a snapshot.
When this WOULD be correct
When the question asks for a mechanism to prevent accidental deletion or modification of a critical resource, such as a production VM or storage account, to enforce governance and compliance policies.
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.
✓Managed disk snapshotCorrect answer▾
Why this is correct
A managed disk snapshot is a read-only, full point-in-time copy of a managed disk that can be taken while the VM remains running. It preserves the exact block-level state of the disk, allowing you to restore the disk to its pre-change state or create a new disk from the snapshot. Because it directly captures the disk's data without requiring downtime or generalization, it is the appropriate artifact for protecting the disk before altering it.
✗Availability setWrong answer — click to see why▾
Why this is wrong here
An availability set is a logical grouping of VMs to ensure high availability across fault domains and update domains; it does not provide point-in-time copies of disks.
★ When this WOULD be the correct answer
When the question asks for a feature that ensures VM redundancy during planned or unplanned maintenance, such as 'You need to deploy two VMs that are placed on different physical hardware to protect against rack failures. What should you create?'
Why candidates choose this
Candidates may confuse availability sets with backup or snapshot capabilities because both are related to protecting VMs, but availability sets focus on uptime, not data recovery.
✗ImageWrong answer — click to see why▾
Why this is wrong here
An image is a template used to create new VMs, not a point-in-time copy of an existing disk for backup or restore purposes.
★ When this WOULD be the correct answer
When you need to create multiple identical VMs from a generalized source, such as deploying a fleet of web servers from a custom OS configuration.
Why candidates choose this
Candidates may confuse 'image' with 'snapshot' because both capture disk state, but images are for deployment templates, not incremental backups.
✗Resource lockWrong answer — click to see why▾
Why this is wrong here
A resource lock prevents accidental deletion or modification of a resource, but it does not create a point-in-time copy of the disk data. It cannot be used to restore the disk to a previous state after a change fails.
★ When this WOULD be the correct answer
When the question asks for a mechanism to prevent accidental deletion or modification of a critical resource, such as a production VM or storage account, to enforce governance and compliance policies.
Why candidates choose this
Candidates may confuse resource locks with backup or snapshot functionality, thinking that locking the resource preserves its state, or they may overestimate the protective capabilities of locks.
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?”
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About these practice questions
Courseiva writes every AZ-104 question from scratch — 1,049 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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-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.