Question 221 of 881
Append Blob for Logging and Archival
You design an application that writes millions of small sensor readings (each ~100 bytes) to Azure Blob Storage. The data is appended to files every minute and after 7 days it is archived for compliance. You need to minimize write costs and storage costs. Which blob type and tier strategy should you use?
Quick Answer
The answer is Append blobs with the Hot tier and a lifecycle rule to move to Archive after 7 days. This combination minimizes write costs because Append blobs are specifically optimized for append operations, allowing you to continuously add small sensor readings without rewriting or modifying existing data, which avoids the higher transaction costs of Block blobs. For storage cost efficiency, a lifecycle management policy automatically transitions the blobs from the Hot tier to the Archive tier after 7 days, leveraging Archive’s lowest-cost storage for compliance data that is rarely accessed. On the AZ-204 exam, this scenario tests your understanding of blob type selection for logging patterns and lifecycle management for cost optimization—a common trap is choosing Block blobs for appending data, which incurs unnecessary overhead. Remember the mnemonic: “Append for append, Archive for archive” to pair the right blob type with the right tier for logging and archival workflows.
⚠ Common exam trap
Many candidates choose block blobs (Option A) assuming they are the default for all data, overlooking the append blob's specific optimization for append operations and the cost benefits of Archive tier for compliance data.
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
✓
Append blobs with Hot tier and a lifecycle rule to move to Archive after 7 days.
Append blobs are optimized for append operations, making them ideal for continuously adding small sensor readings without rewriting existing data, which minimizes write costs. Moving the blobs to the Archive tier after 7 days via a lifecycle rule reduces storage costs for compliance data, as Archive is the lowest-cost tier for infrequently accessed 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.
- ✗
Block blobs with Hot tier and a lifecycle rule to move to Cool after 7 days.
Why it's wrong here
Block blobs require creating new blocks for each append, which is inefficient for frequent small appends; Cool after 7 days is not the cheapest long-term option.
- ✓
Append blobs with Hot tier and a lifecycle rule to move to Archive after 7 days.
Why this is correct
Append blobs are ideal for append-heavy workloads, Hot tier optimizes write performance, and Archive provides the lowest cost for compliance data not accessed frequently.
- ✗
Page blobs with Premium tier.
Why it's wrong here
Page blobs are for VHDs and random read/write patterns, not append; Premium tier is expensive and not needed for this scenario.
- ✗
Append blobs with Cool tier and no lifecycle rule.
Why it's wrong here
Cool tier has lower storage but higher write costs; without lifecycle, data remains in Cool tier, which is more expensive than Archive for long-term retention.
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 |
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 →
Same concept, more angles
1 more way this is tested on AZ-204
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An application writes millions of small log entries (500 bytes each) daily. The logs are rarely read, and when read, they are accessed sequentially. You need to minimize storage costs and maximize write throughput. Which Azure Blob Storage type should you use?
medium- A.Block Blob
- B.Page Blob
- ✓ C.Append Blob
- D.Archive Blob
Why C: Append Blob is optimized for append operations, making it ideal for logging scenarios where new data is continuously added to the end of the blob. It provides high write throughput for small, sequential writes (like 500-byte log entries) and lower storage costs compared to Block Blob for this pattern, as it avoids the overhead of managing multiple blocks per append. Additionally, Append Blob supports sequential read access efficiently, matching the rare, sequential read requirement.
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.
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.