AZ-900 Concepts
Explained One at a Time
Short, focused guides on the specific concepts that trip candidates up most often — each with a practice question at the end.
The responsibility ladder, explained clearly.
LRS, ZRS, GRS, and GZRS — what each protects against.
Who can act, versus what is allowed to exist.
Two layers of resilience, at different scales.
Matching pricing models to workload type.
Identity, MFA, and Conditional Access.
Why AZ-900 is a test of distinctions
AZ-900 is not a hands-on exam. You will never be asked to configure anything. What it tests, over and over, is whether you can tell apart two or three Azure options that sound similar and choose the one that fits a business requirement. Most wrong answers are real, correct Azure features, just not the right one for that scenario.
The six guides below cover the distinctions that come up most often in our question bank and that candidates most often get wrong. Each one explains the difference in plain language and ends with an exam-style question.
Where each concept sits in the exam
| Concept | Exam domain | The question it answers |
|---|---|---|
| IaaS vs PaaS vs SaaS | Cloud Concepts | How much of the stack do you still manage? |
| Availability zones vs region pairs | Architecture & Services | What failure are you protecting against: a datacentre or a whole region? |
| Storage redundancy | Architecture & Services | How many copies of the data exist, and where? |
| Microsoft Entra ID | Architecture & Services | How are identities verified, and on what conditions? |
| RBAC vs Azure Policy | Spans both: identity and governance | Who may act, versus what is allowed to exist? |
| Reserved vs Spot pricing | Management & Governance (cost) | Is the workload steady, or can it be interrupted? |
How to study with these guides
- Read the guide and write the distinction as one line, for example: "RBAC controls people, Policy controls resources."
- Answer the practice question before reading the explanation, then say why each wrong option is wrong.
- Run a 10-question Quick Drill in the matching domain to see the concept used in different scenarios.
- Finish with a full AZ-900 mock test once your drill scores pass 80%.
For a one-page summary of the service pickers and traps, see the AZ-900 cheat sheet.