The 5 AZ-305 Case Studies That Trip Up Every Azure Architect (And How to Nail Them)

The AZ-305 is not a memorization exam. It's a judgment exam.

Microsoft gives you scenarios — messy, real-world scenarios with competing requirements — and asks you to design solutions. There's no "which Azure service does X" trivia here. It's "given these business constraints, technical requirements, and budget limits, what architecture would you choose?"

After helping a dozen colleagues prepare for this cert, I've noticed the same five case study patterns tripping people up over and over. Let's fix that.

Case Study #1: The "We Need High Availability But Can't Afford It" Trap

The scenario gives you a company that needs 99.99% uptime but has a limited budget.

The trap: Picking the most available option regardless of cost.

The fix: Always check the stated SLA requirement against Azure's published SLAs. A single VM with premium SSD gives 99.9%. Two VMs in an Availability Set give 99.95%. Availability Zones give 99.99%. Don't over-engineer.

Case Study #2: The Identity Architecture Maze

You get a company with on-premises AD, Azure AD, and B2B partners.

The trap: Defaulting to Azure AD Connect for everything.

The fix:

• Internal employees syncing from on-prem → Azure AD Connect
• Partners accessing your apps → Azure AD B2B
• Customers signing up for your service → Azure AD B2C
• Applications accessing Azure resources → Managed Identities

Case Study #3: The Data Residency Curveball

A European company needs to keep all data within the EU due to GDPR.

The trap: Suggesting paired regions without checking if both are in the EU.

The fix: Know the key European region pairs. Also know that you can use customer-managed failover with Azure Storage.

Case Study #4: The Microservices Decision Tree

Company wants to modernize a monolithic app.

The trap: Always picking AKS because "Kubernetes is the answer."

The fix:

• Simple web apps → App Service
• Event-driven, short-lived → Azure Functions
• Containerized microservices (moderate scale) → Container Apps
• Complex orchestration, custom networking → AKS

Case Study #5: The Hybrid Networking Nightmare

On-prem datacenter needs to connect to Azure.

The trap: Picking ExpressRoute for everything.

The fix:

• Budget-conscious → VPN Gateway (S2S)
• High bandwidth + low latency → ExpressRoute
• Both + encryption → ExpressRoute with VPN Gateway (ExpressRoute doesn't encrypt by default!)

How to Practice Case Studies

1. Microsoft Learn case studies — Do every single one.
2. AZ-305 practice questions on ExamCert — Scenario-based questions. $4.99 lifetime access with money-back guarantee.
3. Build actual architectures — Draw them in Visio or draw.io.
4. John Savill's AZ-305 Masterclass — Free on YouTube.

Exam Day Advice

• Budget 5-6 minutes for case study initial read, then 2-3 minutes per question.
• Read requirements TWICE before looking at answers.
• When stuck, pick the simpler, cheaper option that meets all requirements.

Average salary for Azure Solutions Architects: $145K-$175K.

Start with free AZ-305 practice tests. ExamCert has hundreds of scenario questions for $4.99.