- A
Azure Blob Storage with hot access tier and Data Lake Storage Gen2.
Why wrong: Hot tier has higher storage cost than cool tier. The scenario requires low cost for data that is rarely updated, so Cool tier is more appropriate.
- B
Azure Table Storage with a timestamp partition key.
Why wrong: Table Storage is optimized for point lookups by partition key and row key, not for scanning large ranges of data by timestamp. Queries would be slower and more expensive at this scale.
- C
Azure Cosmos DB with SQL API and automatic indexing.
Why wrong: Cosmos DB offers low-latency queries but is significantly more expensive than Blob Storage for high-volume append-only data. It is not the most cost-effective solution.
- D
Azure Blob Storage with cool access tier and Azure Data Lake Storage Gen2.
ADLS Gen2 provides the capabilities of Blob Storage with a hierarchical namespace, enabling efficient analytical queries. Cool tier minimizes cost for data that is queried daily but infrequently modified.
AZ-204 Develop for Azure storage Practice Question
This AZ-204 practice question tests your understanding of develop for azure storage. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You need to store billions of small telemetry data entries (each ~100 bytes) from IoT devices. The data is written once and rarely updated. You need to run analytical queries on the last 30 days of data daily. The queries scan large ranges of data by timestamp and require sub-second response times. You need the lowest storage cost while meeting query latency requirements. Which Azure Storage solution should you use?
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
Azure Blob Storage with cool access tier and Azure Data Lake Storage Gen2.
Option D is correct because Azure Blob Storage with the cool access tier provides the lowest storage cost for data that is written once and rarely accessed, while Azure Data Lake Storage Gen2 enables hierarchical namespace and POSIX-like access, allowing efficient analytical queries on large timestamp-ranged data with sub-second response times via partitioning and parallel processing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure Blob Storage with hot access tier and Data Lake Storage Gen2.
Why it's wrong here
Hot tier has higher storage cost than cool tier. The scenario requires low cost for data that is rarely updated, so Cool tier is more appropriate.
- ✗
Azure Table Storage with a timestamp partition key.
Why it's wrong here
Table Storage is optimized for point lookups by partition key and row key, not for scanning large ranges of data by timestamp. Queries would be slower and more expensive at this scale.
- ✗
Azure Cosmos DB with SQL API and automatic indexing.
Why it's wrong here
Cosmos DB offers low-latency queries but is significantly more expensive than Blob Storage for high-volume append-only data. It is not the most cost-effective solution.
- ✓
Azure Blob Storage with cool access tier and Azure Data Lake Storage Gen2.
Why this is correct
ADLS Gen2 provides the capabilities of Blob Storage with a hierarchical namespace, enabling efficient analytical queries. Cool tier minimizes cost for data that is queried daily but infrequently modified.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose Azure Cosmos DB (Option C) for its low-latency queries, overlooking that its cost model (RU/s) makes it prohibitively expensive for scanning billions of small records, while Blob Storage with Data Lake Storage Gen2 provides the required performance at a fraction of the cost when using proper partitioning and file formats.
Trap categories for this question
Scenario analysis trap
Hot tier has higher storage cost than cool tier. The scenario requires low cost for data that is rarely updated, so Cool tier is more appropriate.
Detailed technical explanation
How to think about this question
Azure Data Lake Storage Gen2 builds on Blob Storage by adding a hierarchical namespace, which allows directory-level operations and ACLs, enabling tools like Apache Spark and Azure Synapse to perform parallel partitioned reads on timestamp-based folder structures (e.g., /year/month/day/hour). The cool access tier offers lower per-GB storage costs (approximately $0.01/GB/month vs. $0.018/GB/month for hot) with a 30-day early deletion penalty, which is acceptable since data is retained for only 30 days. The sub-second query latency is achieved by using columnar formats like Parquet and partitioning by timestamp, allowing predicate pushdown to skip irrelevant files.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Develop for Azure storage — study guide chapter
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Develop for Azure storage practice questions
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FAQ
Questions learners often ask
What does this AZ-204 question test?
Develop for Azure storage — This question tests Develop for Azure storage — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Azure Blob Storage with cool access tier and Azure Data Lake Storage Gen2. — Option D is correct because Azure Blob Storage with the cool access tier provides the lowest storage cost for data that is written once and rarely accessed, while Azure Data Lake Storage Gen2 enables hierarchical namespace and POSIX-like access, allowing efficient analytical queries on large timestamp-ranged data with sub-second response times via partitioning and parallel processing.
What should I do if I get this AZ-204 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 2026
This AZ-204 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-204 exam.
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