Azure Storage summary: the AZ-900 storage facts that get tested

Blob tiers, Blob vs Files vs Disk, managed disks and redundancy — the storage decisions AZ-900 actually checks, in one scannable pass. 2026 edition.

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Azure Storage on AZ-900 is not an architecture puzzle — it is a set of vocabulary decisions the exam checks over and over. Learn to make each one quickly and you have banked most of the storage marks. This summary is the shortcut: the facts that get tested, in the order you decide them.

First decision: which service?

The exam almost always starts by describing a workload and asking which storage service fits. The right-hand panel of the diagram above is the whole answer.

Blob Storage — object storage for unstructured data: images, video, backups, logs, anything you count in the millions. This is also the only one of the three that has access tiers.
Azure Files — a managed file share several machines mount over SMB or NFS. The tell is “a shared drive” or “multiple machines need the same files.”
Managed disks — block storage attached to a single VM as its OS and data drives, persisting across stop and start. The tell is “a virtual machine needs a durable drive.”

One line to carry in: objects → Blob, shared file share → Files, a VM’s drive → Disk.

Second decision: which Blob access tier?

Once you are in Blob Storage, the exam tests the cost-versus-access trade shown on the left of the diagram. Read the ladder top to bottom:

Tier	Best for	Read speed
Hot	Data accessed frequently	Instant
Cool	Infrequent, kept ≥30 days	Instant
Cold	Rarely accessed, kept longer	Instant
Archive	Long-term, almost never read	Offline — rehydrate first

Going down the ladder, storage gets cheaper but access gets slower and pricier. The one fact that trips people: Archive is offline. You cannot read an archived blob directly — you rehydrate it back to Hot or Cool first, and that takes time. Pick the tier by how often you read, not by the sticker price of storage.

Third decision: how redundant?

Redundancy is a separate axis from tiers — how many copies exist and how far apart:

LRS (Locally Redundant Storage) — three copies in one datacenter. Cheapest, but a whole-datacenter loss takes the data.
ZRS (Zone-Redundant Storage) — copies across availability zones in the region. Survives one datacenter failing.
GRS (Geo-Redundant Storage) — copies in a second, distant region. Survives a regional outage.

The pattern is simply reach: same building, across zones, across regions. Match the option to the failure the question describes — a zone failure wants ZRS, a regional disaster wants GRS. Reaching further than the scenario needs is the classic distractor.

Storage accounts, briefly

Blobs, file shares and other data live inside a storage account — the top-level container that holds a name, a chosen redundancy level and access settings. You do not need its internals for AZ-900, only that it is the wrapper you create first.

How to use the questions below

Answer each one before you open the explanation, and when you miss, read past the correct option to why the others are wrong — the distractors here are the right service or tier offered for the wrong reason. Getting the reason right is what survives into the exam. For the wider service map, see the Azure architecture and services domain and the compute summary; for one-page recall, the AZ-900 cheat sheet.

Two panels. Left: a cost-and-access ladder of Blob access tiers from Hot (most frequent access, lowest storage cost tier for active data, instant read) down through Cool and Cold to Archive (rarely accessed, cheapest storage, but offline and needing rehydration before you can read). Right: a use-case picker showing Blob Storage for unstructured objects like images, backups and logs; Azure Files for a shared SMB or NFS file share several machines mount; and Managed Disks for the operating-system and data drive attached to a single Azure virtual machine.

6 free AZ-900 practice questions

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AZ-900 Question 1 of 6

Data is read many times a day and must be available instantly. Which Blob access tier fits, and why?

Answer: A — Hot — designed for frequently accessed data, with the lowest access cost and instant reads

The Hot tier is built for data accessed frequently: its per-gigabyte storage price is higher but its access cost is lowest, and reads are instant. Why not the others: Archive is offline and must be rehydrated before you can read it, so it never suits instant, frequent access. Cool has cheaper storage but higher access charges, so it loses money on data read all day. And 'cold data is read most often' is a contradiction — cold means rarely accessed. Pro tip: pick the tier by how often you read, not by the storage price alone.

AZ-900 Question 2 of 6

Which statement about the Archive access tier is correct?

Answer: A — It offers the lowest storage cost but data is offline and must be rehydrated before it can be read

Archive is the cheapest tier to store rarely accessed, long-term data such as compliance backups — but the data is offline, so you must rehydrate it (change its tier) before reading, which takes time. Why not the others: it is not instant like Hot, it is the cheapest to store rather than the most expensive, and it does not silently move data back on read — rehydration is an explicit, timed operation. Pro tip: Archive = cheapest to keep, slowest to get back.

AZ-900 Question 3 of 6

Several virtual machines need to mount the same file share over SMB. Which storage service fits best?

Answer: A — Azure Files — a fully managed file share accessible over SMB or NFS

Azure Files gives you a managed file share that multiple machines can mount concurrently over the SMB or NFS protocol — exactly the shared-drive use case. Why not the others: Blob Storage is object storage addressed over HTTP, not a mounted file share. A standard managed disk attaches to a single VM, not to many at once. And emailing files around is not a storage service. Pro tip: 'shared drive several machines mount' = Azure Files.

AZ-900 Question 4 of 6

You need to store millions of images, log files and backups as unstructured objects. Which service is designed for this?

Answer: A — Blob Storage — object storage for unstructured data like images, backups and logs

Blob Storage is Azure's object store, built for large amounts of unstructured data — images, video, backups, logs — and it is where the access tiers (Hot, Cool, Cold, Archive) apply. Why not the others: a managed disk is block storage for a VM, not an object store. Azure Files is a shared file share, workable but not the purpose-built object store for millions of blobs. And Azure certainly can store unstructured data — that is Blob's whole job. Pro tip: 'unstructured objects at scale' = Blob.

AZ-900 Question 5 of 6

An Azure virtual machine needs a durable operating-system drive and a data drive that persist when the VM is stopped. What provides them?

Answer: A — Azure managed disks — block storage that Azure provisions and manages, attached to the VM

Azure managed disks are block-level storage volumes that Azure provisions and manages for you; they attach to a VM as its OS and data disks and persist across stop/start. Why not the others: Blob containers are not mounted as a VM's system drive. A VM does not boot from an Azure Files share. And managed disks are durable, not temporary — the temporary disk is a separate, non-persistent scratch disk. Pro tip: 'persistent VM drive' = managed disk.

AZ-900 Question 6 of 6

A workload must survive an entire Azure datacenter (availability zone) failing within one region. Which redundancy option meets that with the least reach?

Answer: A — ZRS — Zone-Redundant Storage, copying data across availability zones in the region

ZRS replicates your data synchronously across separate availability zones inside the region, so one zone (datacenter) failing does not lose the data — and it does this without reaching to a second region. Why not the others: LRS keeps all three copies in a single datacenter, so a whole-datacenter loss takes the data with it. GRS does protect against a regional outage, but that is more reach than a single-zone failure needs. And a redundancy option absolutely can cover a zone failure — that is what ZRS is for. Pro tip: same building = LRS, across zones = ZRS, across regions = GRS.

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Frequently asked questions

What is the difference between Blob access tiers and redundancy options?

They are two different axes. Access tiers (Hot, Cool, Cold, Archive) trade storage cost against how quickly and cheaply you can read the data. Redundancy (LRS, ZRS, GRS) decides how many copies exist and how far apart — one datacenter, across zones, or across regions. You choose a tier and a redundancy level independently.

Is the Archive tier instant to read?

No. Archive is the cheapest tier to store rarely accessed data, but the data is offline. To read it you first rehydrate it — change its tier back to Hot or Cool — which takes time. If you need instant reads, Archive is the wrong tier.

Are these real AZ-900 exam questions?

No. They are our own questions, written in the style and difficulty of AZ-900. Copying real exam items violates Microsoft's certification agreement and teaches you nothing about the question you have not seen. The point is to practise the reasoning, not to memorise answers.

Updated for AZ-900 (July 2026). The sample questions above are our own work in the style of the exam — not real exam items. The exam itself is set and marked by the certification body.