Describe considerations for working with non-relational data on Azure →easyMultiple ChoiceObjective-mapped
DP-900 Practice Question: Describe considerations for working with non-relational data on Azure
A medical imaging company stores high-resolution MRI scans in Azure Blob Storage. The scans are accessed frequently for the first 6 months after being generated, then rarely after that, but must be available immediately when accessed for comparisons. The company wants to minimize storage costs. Which Azure Blob Storage access tier should they use for scans older than 6 months?
⚠ Common exam trap
Many exam-takers confuse 'rarely accessed' with 'Archive tier,' forgetting that Archive requires hours of rehydration time, which fails the 'available immediately' constraint in the question.
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 access tier
The Cool access tier is ideal for data that is infrequently accessed but must be available immediately when needed. It offers lower storage costs than the Hot tier while maintaining low-latency retrieval, matching the requirement for scans older than 6 months that are rarely accessed but require instant availability.
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 access tier
Why it's wrong here
Hot is intended for data that is accessed frequently, and it carries higher monthly storage costs and higher data-retrieval rates than Cool or Archive. Because the older scans are accessed only occasionally, choosing Hot would pay a premium for throughput and low latency that the application does not need. A cost-optimized design would reserve Hot only for newly generated MRIs that are read multiple times during the first days of treatment.
When this WOULD be correct
If the question specified that the MRI scans are accessed frequently throughout their entire lifecycle (e.g., for ongoing treatment planning) and cost minimization is not the primary goal, then Hot tier would be correct to optimize for access performance.
- ✓
Cool access tier
Why this is correct
Because older MRI scans are rarely accessed but must be instantly retrievable during follow-ups or legal review, the Cool tier is the optimal trade-off. Cool charges lower per-gigabyte storage fees than Hot while preserving zero-latency reads, so you avoid the high cost of Hot without accepting the multi-hour rehydration delay of Archive. This matches the requirement to minimize cost while maintaining immediate availability.
- ✗
Archive access tier
Why it's wrong here
Archive is the cheapest storage option, but it is designed as offline storage and requires a rehydration job to move blobs to an online tier before they can be read. This rehydration process can take up to 15 hours, depending on the selected priority, which directly violates the stated need for immediate availability of MRI scans. Even with high-priority rehydration, the delay plus the per-operation rehydration cost makes Archive unsuitable for this scenario.
When this WOULD be correct
A question where data is rarely accessed, immediate availability is not required, and the primary goal is minimizing storage costs above all else—e.g., 'A company stores backup tapes that are accessed only for annual audits and can tolerate a 24-hour retrieval delay.'
- ✗
Premium access tier
Why it's wrong here
Premium persists data on powerful SSD-backed infrastructure and guarantees very low latency and high transaction throughput, making it ideal for real-time streaming or high-frequency analytics. That hardware and performance comes at a significantly higher price per gigabyte and per operation, so storing rarely accessed historical MRI scans in Premium wastefully consumes most of the storage budget. Since the business need is primarily cheap storage with occasional reads, this tier offers unnecessary performance that cannot be cost-justified.
When this WOULD be correct
A question where the requirement is for the lowest possible latency for frequently accessed data, such as real-time medical image retrieval during surgery, and cost is not the primary concern. Premium tier would be correct for high-performance needs.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DP-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Cool access tierCorrect answer▾
Why this is correct
Because older MRI scans are rarely accessed but must be instantly retrievable during follow-ups or legal review, the Cool tier is the optimal trade-off. Cool charges lower per-gigabyte storage fees than Hot while preserving zero-latency reads, so you avoid the high cost of Hot without accepting the multi-hour rehydration delay of Archive. This matches the requirement to minimize cost while maintaining immediate availability.
✗Hot access tierWrong answer — click to see why▾
Why this is wrong here
The Hot tier is designed for data accessed frequently, but the question states that scans older than 6 months are rarely accessed. Using Hot would incur higher storage costs without benefit, as Cool tier provides lower cost for infrequently accessed data with immediate availability.
★ When this WOULD be the correct answer
If the question specified that the MRI scans are accessed frequently throughout their entire lifecycle (e.g., for ongoing treatment planning) and cost minimization is not the primary goal, then Hot tier would be correct to optimize for access performance.
Why candidates choose this
Candidates may assume that 'immediate availability' requires Hot tier, overlooking that Cool tier also offers low-latency access. They might also default to Hot as the default tier without considering cost implications for infrequent access.
✗Archive access tierWrong answer — click to see why▾
Why this is wrong here
The Archive tier has the lowest storage cost but requires hours to rehydrate data before access, violating the requirement that scans must be available immediately when accessed.
★ When this WOULD be the correct answer
A question where data is rarely accessed, immediate availability is not required, and the primary goal is minimizing storage costs above all else—e.g., 'A company stores backup tapes that are accessed only for annual audits and can tolerate a 24-hour retrieval delay.'
Why candidates choose this
Candidates see 'rarely accessed' and 'minimize storage costs' and assume Archive is the cheapest option, overlooking the critical 'available immediately' constraint.
✗Premium access tierWrong answer — click to see why▾
Why this is wrong here
The Premium access tier is designed for low-latency, high-performance scenarios with frequent access, not for minimizing costs on rarely accessed data. It has higher storage costs than Cool or Archive tiers, making it unsuitable for scans older than 6 months that are rarely accessed.
★ When this WOULD be the correct answer
A question where the requirement is for the lowest possible latency for frequently accessed data, such as real-time medical image retrieval during surgery, and cost is not the primary concern. Premium tier would be correct for high-performance needs.
Why candidates choose this
Candidates may mistakenly think 'Premium' implies better cost savings or assume it's the default best tier, overlooking that it's optimized for performance, not cost efficiency for infrequent access.
Analysis generated from the official DP-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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
Learn chapter
Data Roles and Core Concepts
Key term
Blob storage
Blob storage is a cloud service for storing large amounts of unstructured data, such as text or binary data, like documents, images, and videos.
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 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 DP-900 exam.