DP-900 Describe core data concepts Practice Question
A multinational corporation needs to store archival data for 10 years with the lowest possible storage cost, while still being able to retrieve it within 24 hours if needed. Which Azure storage tier should they use?
⚠ Common exam trap
Many candidates confuse 'lowest storage cost' with 'lowest overall cost' and overlook the retrieval time constraint, mistakenly choosing Cool Blob Storage because it offers lower cost than Hot but still allows immediate access, ignoring that Archive is even cheaper and meets the 24-hour retrieval window.
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
✓
Archive Blob Storage
Archive Blob Storage is the correct choice because it is designed for long-term retention of data that is rarely accessed, offering the lowest storage cost among Azure blob tiers. The 10-year retention requirement and 24-hour retrieval window align perfectly with Archive's capabilities, as data can be rehydrated to a hot or cool tier within hours (typically up to 15 hours for standard priority rehydration).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Archive Blob Storage
Why this is correct
Archive Blob Storage is the correct choice because it offers the lowest storage cost of any Azure Blob access tier, which aligns with the archival requirement. Data is stored offline without instant access, but the service supports rehydration within up to 15 hours—well within the stated 24-hour retrieval window. The latency is acceptable here because the workload prioritizes cost minimization over immediate availability.
- ✗
Cool Blob Storage
Why it's wrong here
Cool Blob Storage is wrong because, while it is cheaper than Hot and provides immediate retrieval, it still has a higher storage cost than Archive. For a dataset that must be kept for long-term archival and only needs to be retrieved within 24 hours, paying more for instant access is unnecessary. The requirement specifically asks for the lowest cost, which Cool does not satisfy even though its access latency is not a problem in this scenario.
- ✗
Premium Blob Storage
Why it's wrong here
Premium Blob Storage is designed for high-performance workloads that require very low and consistent latency, typically for transactional data or frequent reads and writes. It charges premium prices and is therefore completely inappropriate for archival data that is rarely accessed and has no need for subsecond response times. Choosing Premium would ignore the cost-minimization goal and provide far more performance than the 24-hour retrieval window demands.
- ✗
Hot Blob Storage
Why it's wrong here
Hot Blob Storage is the most expensive access tier because it is optimized for high-frequency access and immediate read/write operations. Archival data, by definition, is accessed infrequently, so using Hot would incur unnecessarily high storage costs without any compensating benefit. The requirement's optional 24-hour retrieval window explicitly permits a slower, cheaper storage solution, making Hot over-engineered and economically wrong.
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
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
Key term
Azure Storage
Azure Storage is Microsoft's cloud-based service for storing data like files, messages, and backups with high durability and scalability.
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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.