AZ-305 Design infrastructure solutions Practice Question
A media company is building a video streaming platform on Azure. The platform will store original high-definition videos and convert them to multiple resolutions for distribution. The company needs a cost-effective storage solution for the original videos, which are accessed infrequently but must be instantly available when needed. The converted videos will be served to end users globally and must be cached at edge locations for low latency. You need to design a storage and content delivery solution. What should you recommend?
⚠ Common exam trap
It's easy for candidates to confuse the Archive tier's low cost with instant availability, overlooking the mandatory rehydration delay, and mistaking Azure Front Door's global load balancing for a CDN caching solution.
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
✓
Store original videos in Azure Blob Storage Cool tier and use Azure CDN for distribution.
Azure Blob Storage Cool tier provides low-cost storage for infrequently accessed data with instant retrieval, meeting the requirement for original videos that are rarely accessed but must be available immediately. Azure CDN caches the converted videos at edge locations globally, ensuring low-latency delivery to end users.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Store original videos in Azure Blob Storage Cool tier and use Azure CDN for distribution.
Why this is correct
Cool tier is cost-effective for original videos that are stored but rarely accessed directly by consumers, because most playback traffic is served from Azure CDN edge caches. With CDN absorbing the majority of end-user requests, the origin store in Cool incurs negligible transaction costs while still offering immediate low-latency retrieval, unlike Archive or the premium cost of Hot. This architecture optimizes both storage spend and streaming performance.
- ✗
Store original videos in Azure Blob Storage Premium tier and use Azure CDN for distribution.
Why it's wrong here
Premium tier delivers the lowest latency and highest transaction throughput at a premium price, but that performance is wasted here because Azure CDN already serves user-facing streaming traffic from edge nodes. The rarely accessed source videos would sit idle in a high-cost SSD-backed blob tier, dramatically increasing storage spend without improving viewer experience. Standard or Cool tiers are sufficient for origin storage, leaving Premium for scenarios requiring high frequency direct access.
- ✗
Store original videos in Azure Blob Storage Archive tier and use Azure CDN for distribution.
Why it's wrong here
Archive tier is designed for long-term archival storage with the lowest cost, but objects must be rehydrated to an online tier before they can be read, a process that can take up to 15 hours (or at best one hour with high-priority rehydration). A CDN cannot serve a video until the origin has produced it, so an uncached request would block or fail during rehydration. This makes Archive unsuitable for any media library that supports on-demand streaming without pre-planned de-archival.
- ✗
Store original videos in Azure Files and use Azure Front Door for caching.
Why it's wrong here
Azure Files provides SMB/NFS file shares for lift-and-shift applications and simple file storage, not a platform for massive, concurrent media streaming; its per-share bandwidth and IOPS limits are easily exhausted by many viewers. Azure Front Door is primarily a global load balancer and CDN for dynamic HTTP(S) applications, but pairing it with a file share forces SMB as the origin protocol and misses the optimized static-object features of Blob storage, such as access tiers, lifecycle management, and CDN-native origin integration. This combination is an architectural mismatch.
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.