AZ-900 Describe Azure architecture and services Practice Question
A company needs to store archival data for 10 years with the lowest possible storage cost. Data may be accessed once a year for compliance audits. Which Azure Storage access tier should they choose?
⚠ Common exam trap
A common mix-up: candidates confuse 'lowest storage cost' with 'lowest overall cost,' forgetting that Archive has higher retrieval and data access charges, but the question explicitly asks for the lowest storage cost, making Archive the correct choice despite the access 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
✓
Archive
The Archive access tier is designed for data that is rarely accessed and has a flexible latency requirement, making it the most cost-effective option for long-term archival storage. With a 10-year retention period and only annual access for compliance audits, Archive provides the lowest storage cost per gigabyte compared to Cool or Hot tiers, though it incurs higher retrieval costs and latency (typically hours to rehydrate data).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cool
Why it's wrong here
The Cool access tier is cheaper than Hot but still more expensive than Archive, and it is designed for data that is infrequently accessed but needs retrieval in minutes, not hours. For data that must be retained for 10 years without any expected use, Cool's storage cost is unnecessarily high, and its low retrieval fee is irrelevant because the data will rarely be restored. Archive is the better fit because it prioritizes minimal storage cost over rapid availability.
When this WOULD be correct
A company needs to store data that is accessed infrequently but at least once every 30 days, with a retention period of less than 90 days, and wants lower storage cost than Hot tier but still needs low-latency access.
- ✗
Hot
Why it's wrong here
The Hot access tier is optimized for data that is accessed or modified frequently, providing low-latency access but at the highest storage price among standard tiers. Storing archival data for 10 years in Hot would mean paying a large storage premium for years with virtually no reads, which is financially inefficient. Hot is intended for active workloads, not for data that will sit untouched for a decade.
When this WOULD be correct
A company needs to store data that is accessed frequently (e.g., multiple times per day) and requires low latency, with the lowest access cost but higher storage cost being acceptable.
- ✓
Archive
Why this is correct
The Archive access tier is the correct choice for 10-year archival because it offers the lowest storage cost of all Azure Storage tiers, specifically designed for data that is rarely accessed. Retrieval can take up to several hours and incurs a higher access charge, but for long-term compliance or backup data that will almost never be read, that trade-off is acceptable. Archive also has a minimum retention period of 180 days, which aligns well with a 10-year requirement.
- ✗
Premium
Why it's wrong here
The Premium tier (Azure Premium Storage) is built for high-performance, low-latency I/O using SSDs, typically for production virtual machines and mission-critical databases. It is not a cost-optimized tier for bulk archival; its cost per gigabyte is dramatically higher than standard or archive tiers. Choosing Premium for 10-year archival would waste enormous money on performance capabilities the data will never use.
When this WOULD be correct
A question requiring sub-millisecond latency for frequently accessed data, such as an Azure virtual machine disk or a high-traffic database, would make Premium the correct choice.
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 AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓ArchiveCorrect answer▾
Why this is correct
The Archive access tier is the correct choice for 10-year archival because it offers the lowest storage cost of all Azure Storage tiers, specifically designed for data that is rarely accessed. Retrieval can take up to several hours and incurs a higher access charge, but for long-term compliance or backup data that will almost never be read, that trade-off is acceptable. Archive also has a minimum retention period of 180 days, which aligns well with a 10-year requirement.
✗CoolWrong answer — click to see why▾
Why this is wrong here
Cool tier is designed for data with moderate access frequency (at least once every 30 days) and has higher storage costs than Archive, making it unsuitable for 10-year archival with only yearly access.
★ When this WOULD be the correct answer
A company needs to store data that is accessed infrequently but at least once every 30 days, with a retention period of less than 90 days, and wants lower storage cost than Hot tier but still needs low-latency access.
Why candidates choose this
Candidates may confuse 'cool' with 'cold' storage, assuming it is the cheapest option for long-term archival, or they may not fully understand the access frequency and cost trade-offs between Cool and Archive tiers.
✗HotWrong answer — click to see why▾
Why this is wrong here
The Hot tier is designed for frequently accessed data and has the highest storage cost, making it unsuitable for archival data accessed only once a year.
★ When this WOULD be the correct answer
A company needs to store data that is accessed frequently (e.g., multiple times per day) and requires low latency, with the lowest access cost but higher storage cost being acceptable.
Why candidates choose this
Candidates may mistakenly think 'Hot' implies low cost due to its name, or they may not understand that Hot tier has high storage costs and is optimized for frequent access, not long-term archival.
✗PremiumWrong answer — click to see why▾
Why this is wrong here
Premium tier is designed for low-latency, high-performance workloads, not for archival data. It incurs the highest storage cost, making it unsuitable for long-term, infrequently accessed data.
★ When this WOULD be the correct answer
A question requiring sub-millisecond latency for frequently accessed data, such as an Azure virtual machine disk or a high-traffic database, would make Premium the correct choice.
Why candidates choose this
Candidates may mistakenly think 'Premium' implies better value or lower cost for long-term storage, or they may confuse it with the 'Archive' tier due to similar naming patterns.
Analysis generated from the official AZ-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?”
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-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 AZ-900 exam.