The answer is enabling Azure CDN to cache the files. This is correct because the CDN serves frequently accessed Parquet files from edge locations, drastically reducing the number of direct read and list transactions against Azure Data Lake Storage Gen2, which directly lowers transaction costs for read-heavy analytics workloads. On the DP-203 exam, this scenario tests your understanding of cost optimization strategies for high-frequency read patterns, often appearing as a trap where candidates mistakenly choose to increase the number of storage accounts or change file formats instead of leveraging caching. A common memory tip is “CDN for read-heavy, not write-heavy”—if the workload were write-intensive, caching would be ineffective. Remember: when you see frequent reads of static Parquet files in a cost question, think “cache at the edge” to slash transaction fees.
DP-203 Practice Question: Monitor and optimize data storage and processing
This DP-203 practice question tests your understanding of monitor and optimize data storage and processing. 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.
A data engineer is monitoring Azure Data Lake Storage Gen2 costs and notices high transaction costs for a specific container. The container stores Parquet files used by Azure Databricks for read-heavy analytics. The files are accessed frequently by multiple jobs. What is the most cost-effective way to reduce transaction costs?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable Azure CDN to cache the files.
Option D is correct because enabling Azure CDN caches the frequently accessed Parquet files at edge locations, reducing the number of direct read requests to Azure Data Lake Storage Gen2. This lowers transaction costs (both read and list operations) while maintaining low-latency access for read-heavy analytics workloads. The CDN serves cached content, so the storage account incurs fewer billable transactions.
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.
✗
Move the data to Azure Blob Storage cool tier.
Why it's wrong here
Cool tier has higher read costs, increasing transaction costs.
✗
Increase the Parquet file size to maximize block size.
Why it's wrong here
While larger files reduce the number of transactions, it may not be practical to change file sizes arbitrarily.
✗
Convert the container to Azure Files.
Why it's wrong here
Azure Files is more expensive for read-heavy analytics and does not reduce transaction costs.
✓
Enable Azure CDN to cache the files.
Why this is correct
Azure CDN caches data at edge locations, reducing the number of direct read transactions to the storage account.
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 assume increasing file size (Option B) reduces costs because fewer files mean fewer transactions, but they overlook that each read of a large file still incurs a single transaction per API call, and transaction costs are per operation, not per file size.
Detailed technical explanation
How to think about this question
Azure CDN caches objects based on cache-control headers or default rules; for read-heavy analytics, setting a long TTL (e.g., 7 days) on static Parquet files ensures most reads are served from edge nodes, bypassing the storage account entirely. Under the hood, CDN uses HTTP GET requests that are billed as egress from the CDN, not as storage transactions, so the per-request cost shifts from storage transaction charges (typically $0.0005 per 10,000 reads) to CDN egress (often cheaper for high-volume reads). A real-world scenario: a Databricks job reading the same 1 GB Parquet file 100 times daily would incur 100 read transactions on ADLS Gen2; with CDN, only the first read hits storage, and subsequent reads are served from the edge, reducing transaction costs by ~99%.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this DP-203 question in full detail.
Monitor and optimize data storage and processing — This question tests Monitor and optimize data storage and processing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable Azure CDN to cache the files. — Option D is correct because enabling Azure CDN caches the frequently accessed Parquet files at edge locations, reducing the number of direct read requests to Azure Data Lake Storage Gen2. This lowers transaction costs (both read and list operations) while maintaining low-latency access for read-heavy analytics workloads. The CDN serves cached content, so the storage account incurs fewer billable transactions.
What should I do if I get this DP-203 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This DP-203 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-203 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.