AZ-305 Design data storage solutions Practice Question
A media company uploads large video files to Azure Blob Storage. Users frequently access recent videos, while older videos are rarely accessed after 30 days. The company wants to minimize storage costs while ensuring that recently accessed videos are immediately available. Which storage tier strategy should you recommend?
⚠ Common exam trap
Watch out — candidates often assume Cool tier is always the cheapest option for infrequent access, but they overlook that Archive tier, while cheaper, introduces unacceptable rehydration delays for the 'immediately available' requirement, and that Hot tier is necessary for the initial high-access period to avoid access costs and latency.
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
✓
Use Hot tier for the first 30 days, then automatically move to Cool tier
It balances cost and performance by using the Hot tier for the first 30 days (when videos are frequently accessed) and then automatically transitioning to the Cool tier via Azure Blob Storage lifecycle management. This ensures immediate availability for recent uploads while minimizing storage costs for older, rarely accessed content. The Cool tier offers lower storage costs than Hot but still provides low-latency access, meeting the requirement that recently accessed videos are immediately available.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Premium tier for all files
Why it's wrong here
Premium tier (block blobs) allocates dedicated high-performance SSDs and per-GB pricing roughly 20-40× higher than Hot, which is unjustifiable when the workload is sequential write-once/read-seldom video. It also lacks lifecycle management integration in the same way, so you cannot tier down automatically after 30 days without a separate rule. The performance benefit (low latency, high IOPS) is irrelevant for large video files whose bottleneck is network throughput, not disk latency.
- ✗
Use Cool tier for all files with lifecycle management to Archive
Why it's wrong here
Cool tier for all files would place the most recent, frequently accessed uploads on media that has a 30-day minimum billable duration and a higher per-GB retrieval cost; users downloading newly published videos would experience added latency and retrieval fees. Lifecycle to Archive adds a further 30-day minimum and up to 15-hour rehydration for any cold misses, so recent content that should be immediately available would suffer. This design optimizes storage cost at the expense of access performance for the freshest files, which is the exact opposite of the access pattern.
- ✓
Use Hot tier for the first 30 days, then automatically move to Cool tier
Why this is correct
Hot tier for the first 30 days gives immediate low-latency access during the peak viewing and editing window, and the lifecycle rule fires automatically to transition blobs to Cool after the access pattern cools down. Cool tier then cuts storage cost by roughly 40-50% while still offering sub-second latency for occasional replays. Because lifecycle evaluation runs once per day, the rule must be set to '30 days after last modification' to avoid a 31-day gap; this simple policy balances cost and availability without manual intervention.
- ✗
Use Archive tier for all files and rehydrate on access
Why it's wrong here
Archive tier is for data that is accessed at most a few times per year; every access requires a rehydration step that can take up to 15 hours (with standard priority) and incurs both read and write operations. For video files that are accessed regularly in the first month, this latency would make the media unusable for immediate playback or editing. Even with rehydration, the higher per-GB retrieval and operation costs can exceed the savings for frequent or periodic access, and lifecycle rules cannot rehydrate automatically for active use without extra orchestration.
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 |
Go deeper
Related to this question
About these practice questions
One of 795 original AZ-305 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.