Why This Capsule?
Azure storage services cover a wide range of options — Blob, File, Queue, Table, SQL, Cosmos DB, redundancy, and hybrid solutions. The AZ-305 exam often tests your ability to choose the right storage solution based on business, performance, and compliance needs.
Many candidates get tripped up because several services sound similar or overlap in features. This capsule highlights common pitfalls, exam strategies, and quick recall tips.
Common Pitfalls to Avoid
1. Blob vs File Storage
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Blob = unstructured object storage (media, logs, backups).
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File = SMB-based file shares (legacy app lift-and-shift).
Exam Trap: If the scenario mentions SMB/NFS file share → Azure Files, not Blob.
2. Queue Storage vs Service Bus
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Queue Storage = simple messaging, cheap, no advanced features.
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Service Bus = advanced enterprise messaging (topics, sessions, transactions).
Exam Trap: If guaranteed ordering or pub-sub model is required → Service Bus, not Queue.
3. Azure SQL vs Managed Instance vs SQL on VMs
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SQL Database = modern apps, low admin overhead.
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Managed Instance = near full SQL Server compatibility.
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SQL on VMs = full control, legacy workloads.
Exam Trap: If SQL Agent or linked servers are required → Managed Instance or SQL VM.
4. Cosmos DB Partitioning
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Choosing poor partition keys leads to hotspots and exam trick questions.
Tip: Pick high-cardinality, evenly distributed keys (like UserID, DeviceID).
5. Storage Redundancy
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LRS = single datacenter.
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ZRS = multiple zones.
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GRS = secondary region (not readable).
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RA-GRS = secondary region with read access.
Exam Trap: If question says “read from secondary region” → RA-GRS, not GRS.
6. Security Mechanisms
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SAS = temporary, time-bound access.
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RBAC = identity-based permanent access.
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CMK = regulatory control over encryption keys.
Exam Trap: If compliance requires control over keys → CMK (via Key Vault), not default encryption.
7. Hybrid Storage
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Azure File Sync = modern solution for extending on-prem file servers.
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StorSimple = legacy, no longer recommended.
Exam Trap: If the scenario is modern, avoid StorSimple answers.
Exam Strategies
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Read the requirements carefully
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If keywords mention regulatory, compliance, encryption keys → Key Vault + CMK.
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If cost optimization for rarely accessed data → Blob Archive tier.
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If low latency global access → Cosmos DB.
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Map services to use cases
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Blob → unstructured storage.
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File → SMB/NFS shares.
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Table → simple NoSQL.
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Queue → lightweight messaging.
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SQL DB/MI/VM → relational workloads.
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Cosmos → high-scale global NoSQL.
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Don’t over-engineer
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If a simple storage account works, don’t jump to Cosmos DB.
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If redundancy is required only inside a region, don’t pick GRS — ZRS may be enough.
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Watch for retired services
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StorSimple → exam trap, File Sync is the replacement.
Quick Recall Table for Exam
| Requirement | Solution |
|---|---|
| Store videos/images | Blob Storage |
| Cloud SMB file share | Azure Files |
| Simple NoSQL, key-value | Table Storage |
| Messaging between apps | Queue Storage |
| Enterprise messaging | Service Bus |
| Cloud-native relational DB | SQL Database |
| Lift-and-shift SQL | Managed Instance |
| Legacy SQL workloads | SQL on VM |
| Global scale NoSQL | Cosmos DB |
| Regional redundancy | ZRS |
| Cross-region with read access | RA-GRS |
| Regulatory encryption control | CMK in Key Vault |
| Extend on-prem file server | Azure File Sync |
Exam Tips
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Expect scenario-based questions (e.g., “Company needs to migrate legacy SQL Server with minimal refactoring”).
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Focus on trade-offs (performance vs cost, management vs control).
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Look for keywords in the question that hint at the correct service.
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Avoid picking answers with retired services (StorSimple).
What to Expect in the Exam
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Direct Q: “Which storage solution provides unstructured, object-based storage with tiering options?” → Blob Storage.
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Scenario Q: “Company requires SQL Server features like SQL Agent in Azure.” → Managed Instance.
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Scenario Q: “Retailer wants multi-region write for global NoSQL.” → Cosmos DB.
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Trick Q: “GRS provides read access to secondary.” → False.