AZ-305 Design data storage solutions Practice Question
A media company stores large video files that are accessed once a month for audits. When needed, they must be available for download immediately (within seconds). The company wants to minimize storage costs. Which Azure Blob Storage access tier should they use?
⚠ Common exam trap
Test-takers frequently choose Archive tier for infrequent access without realizing that the multi-hour rehydration latency makes it impossible to meet the 'within seconds' availability requirement, or they choose Hot tier out of habit for any access speed requirement, ignoring the cost-minimization goal.
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
✓
Cool tier
The Cool tier is optimal for this scenario because it balances low storage cost with high availability and low latency access. Video files accessed once a month for audits require immediate download (within seconds), which Cool tier supports with the same millisecond latency as Hot tier, but at a lower storage price. Archive tier would introduce a multi-hour rehydration delay, making it unsuitable for on-demand access within seconds.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Hot tier
Why it's wrong here
Hot tier is designed for frequently accessed data and carries the highest per-GB storage price, with no early-deletion penalty but premium capacity costs. Since the video files are touched only once each month, you would be provisioning high-cost storage for long idle periods, making it economically unjustified. The access latency is identical to Cool tier, so you gain no operational benefit that compensates for the extra storage expense.
- ✓
Cool tier
Why this is correct
Cool tier offers a low per-GB storage price with a modest per-GB retrieval fee and a 30-day minimum retention period, which aligns perfectly with monthly access. Retrieval is immediate because objects remain in the online tier, so the media company can read or stream the video without waiting for rehydration. For large files read once per month, Cool delivers the lowest total cost among tiers that still provide on-demand access, making it the correct choice.
- ✗
Cold tier
Why it's wrong here
Cold tier lowers the base storage cost but imposes a higher per-GB retrieval fee and a mandatory 90-day retention period, which does not match a 30-day access cadence. Over the course of a year, the cumulative retrieval charges for twelve monthly reads can quickly erase the storage savings relative to Cool tier. Additionally, the 90-day minimum means you would either pay early-deletion fees or keep data longer than the business needs, further increasing cost.
- ✗
Archive tier
Why it's wrong here
Archive tier is the least expensive for static data, but it stores blobs in an offline state that requires manual rehydration to a readable tier, a process that can take up to 15 hours. For a media company that must access a video every month, this delay is operationally unacceptable, and rehydration also incurs additional read and write costs. Even if you schedule the rehydration in advance, the complexity and unpredictability make Archive unsuitable for a predictable 30-day access pattern.
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.