AZ-305 Design data storage solutions Practice Question
A company needs to store millions of small JSON files (average 10 KB each) for a serverless application. The data must be accessed via HTTPS and support high read throughput. Which Azure storage solution is most cost-effective?
⚠ Common exam trap
It's easy for candidates to choose Azure Cosmos DB for JSON files due to its native JSON support, but they overlook the cost inefficiency of using a transactional database for static file storage, where blob storage provides the same HTTPS access at a fraction of the cost.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Blob Storage (general-purpose v2, hot tier)
Azure Blob Storage (general-purpose v2, hot tier) is the most cost-effective solution because it provides native HTTPS access, high throughput for read-heavy workloads, and low-cost storage for small objects like JSON files. The hot tier optimizes for frequent access, and GPv2 accounts support the high request rates needed for millions of small files without premium pricing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Azure Blob Storage (general-purpose v2, hot tier)
Why this is correct
Azure Blob Storage (general-purpose v2) is purpose-built for storing massive numbers of small, unstructured objects like JSON files. It exposes a REST API over HTTPS, allows per-blob metadata and tags, and supports hot/cool/archive lifecycle management. The hot tier optimizes for frequent reads, making it both cost-effective and highly scalable for millions of entries.
- ✗
Azure Files (standard)
Why it's wrong here
Azure Files (standard) provides managed SMB/NFS file shares, not an HTTP object store. It is designed for lift-and-shift file servers or applications that mount a drive, and accessing small JSON files individually over HTTPS is not a native pattern. Standard shares also have latency/concurrency characteristics that would degrade with millions of tiny random reads.
- ✗
Azure Cosmos DB
Why it's wrong here
Azure Cosmos DB is a multi-model NoSQL database that charges per request unit (RU) and is not optimized for storing opaque blobs. Each document/item has a 2 MB size limit, so many JSON files would either exceed it or waste database capacity. Using Cosmos for simple blob storage would incur far higher cost and administrative overhead than Blob Storage.
- ✗
Azure Table Storage
Why it's wrong here
Azure Table Storage is a NoSQL key-value service for structured entities with typed properties, not arbitrary file content. It imposes a 1 MB entity size limit and does not support navigating or serving complete JSON objects as a REST resource. Table Storage is suited for querying records (e.g., user sessions) rather than storing hundreds of thousands of small files.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-305 exam.