AZ-305 exam tips: how to answer design questions
The best AZ-305 tip is to treat every question as a requirements check, not a knowledge check: find the constraint that rules out most options, then pick the remaining answer with the least operational overhead. Most wrong answers on this exam are correct services chosen for the wrong requirement. These tips show how to read, rank and eliminate.
Read the requirement before the options
Scenario questions bury the deciding detail. Underline mentally:
- Numbers: RPO, RTO, availability percentages, user counts, data volumes.
- Scope words: “region”, “datacenter”, “global”, “on-premises”.
- Preference words: “minimal administration”, “lowest cost”, “least privilege”, “without code changes”.
- Hard constraints: compliance, data residency, existing licences, an application that cannot change.
Then read the options. Cross out any that fail a hard constraint before you compare the rest.
Use the default ranking
When two options both work, Microsoft-style design answers usually favour:
- The more managed service over the one you administer yourself.
- The narrower scope over the broader one, for access.
- The native feature over a custom build.
- The cheapest option that still meets the stated objectives, not the strongest.
Watch for the reverse: “needs OS-level access” or “uses unsupported feature” justifies a less managed choice.
Know the pairs that are always confused
| Pair | Deciding detail |
|---|---|
| Service Bus vs Event Grid vs Event Hubs | Message with settlement vs event notification vs stream |
| Front Door vs Application Gateway | Global vs regional layer 7 |
| Front Door vs Traffic Manager | HTTP edge service vs DNS-only routing |
| Recovery Services vault vs Backup vault | VMs and files vs disks and blobs |
| Site Recovery vs Azure Backup | Replication and failover vs restore points |
| SQL Database vs Managed Instance | New app vs SQL Server compatibility |
| Managed identity vs service principal | No secret to manage vs secret you rotate |
| ZRS vs GRS | Datacenter failure vs regional failure |
| Private endpoint vs service endpoint | Private IP in your VNet vs optimised route to the public endpoint |
If you can state each deciding detail in a few words, a third of the exam gets easier.
Convert recovery objectives quickly
| If the scenario says | Think |
|---|---|
| RPO of seconds, regional disaster | Failover group or geo-replication |
| RPO of hours, cheap | Backup with geo-restore |
| VM workloads, RTO of an hour | Site Recovery |
| Survive a datacenter failure | Zones or ZRS |
| Survive accidental deletion | Soft delete, versioning, backup |
Replication protects against site loss, not against deletion or corruption, because it copies the damage too. Backup protects against the second.
Handle the formats
Case studies. Read the requirements and the existing environment first, answer the questions that follow, and expect later questions to add constraints. Skim the long text for numbers and named systems, not for prose. Questions in a case study often ask you to choose different parts of one design.
Yes/no series. One scenario, several proposed solutions, each judged independently. Several can be correct. Judge each one against every requirement, and do not assume that exactly one is right.
Drag and drop. Usually matches services to requirements or orders steps. Use each item once unless told otherwise.
Manage time
Move steadily, flag uncertain items and return to them, and do not spend minutes on a single question early. Check the exact time allowed in your appointment details, since Microsoft does not state it on the exam page. Read the exam format for the rest of the mechanics.
Prepare the right way
Study by decision, not by service. For each service, write what it is for, what it is not for and the nearest alternative. Use the study plan, then test yourself with the practice test. A final pass through the cheat sheet puts the pairs above where you can recall them under pressure.
On the day
Sleep, arrive early, and follow the proctor rules. The exam day guide covers identification, the online check-in and what to do if something goes wrong. If you are unsure whether you are ready, see the readiness checklist at the end of the study plan, or is AZ-305 hard?.