AZ-305 Design data storage solutions Practice Question
A company needs to store large amounts of unstructured data (log files) for analytics. The data is accessed frequently for the first 30 days, then occasionally for the next 90 days, and rarely after that but must be retained for 7 years for compliance. The data must not be modified or deleted during the retention period, and administrative access must not be able to bypass this restriction. They want to minimize storage costs. Which combination of Azure Blob Storage features should they configure?
⚠ Common exam trap
Test-takers frequently confuse soft delete or legal hold with immutable retention policies, not realizing that only a locked time-based retention policy provides true WORM protection that cannot be bypassed by administrators.
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
✓
Configure a lifecycle management policy to move blobs to Cool tier after 30 days and to Archive tier after 120 days. Apply a time-based retention policy with a retention period of 2,555 days and lock it.
It combines a lifecycle management policy to automatically transition blobs from Hot to Cool after 30 days and to Archive after 120 days, minimizing storage costs. The time-based retention policy with a locked retention period of 2,555 days (7 years) ensures that blobs cannot be modified or deleted during the retention period, and locking the policy prevents administrative bypass, meeting the compliance requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure a lifecycle management policy to move blobs to Cool tier after 30 days and to Archive tier after 120 days. Apply a time-based retention policy with a retention period of 2,555 days and lock it.
Why this is correct
A locked time-based retention policy on the container ensures that blobs cannot be deleted or overwritten for the specified duration (7 years = 2555 days). Lifecycle management moves blobs to cost-efficient tiers. Locking prevents bypass.
- ✗
Enable soft delete and versioning on the storage account, and use a custom script to delete blobs after 7 years. Manually move blobs to Cool and Archive tiers using Azure PowerShell.
Why it's wrong here
Soft delete and versioning protect against accidental or malicious deletion only within the configured retention window and do not guarantee immutability—an administrator with delete or overwrite permissions can still purge versions or disable the protection. A custom script that deletes blobs after 7 years is an out-of-band process that can fail due to permissions, service principal expiry, or throttling, and manual tier moves via PowerShell are neither automated nor reliably scheduled, leaving cost management and compliance enforcement to human intervention. In contrast, a locked time-based retention policy prohibits both deletion and overwrites for the entire 7-year period at the container level, and lifecycle management transitions tiers deterministically.
- ✗
Set each blob's access tier to Cool on upload, then manually change to Archive after 30 days. Enable Azure Backup on the storage account for retention.
Why it's wrong here
Setting the access tier to Cool on upload only affects storage pricing, not data retention or immutability; blobs in the Cool tier can still be overwritten or deleted at any time by an authorized user. Manually changing each blob to Archive after 30 days is not scalable and is prone to mistakes, missed jobs, or incomplete transitions, especially at enterprise scale, whereas lifecycle management applies rules automatically and idempotently. Azure Backup on the storage account creates recovery point snapshots but does not prevent ongoing writes or deletions, nor does it enforce a required retention period—it simply provides point-in-time restore capabilities, so it fails the core compliance requirement of prohibiting any modification for 2,555 days.
- ✗
Apply a legal hold on the container to prevent deletion, and configure a lifecycle policy to move blobs to Archive after 30 days.
Why it's wrong here
A legal hold prevents deletion of blobs in the container, but it does not block overwrites or modifications—an authorized user can still change the content of an existing blob, which is insufficient for a strict time-based retention requirement. Additionally, legal hold is a manual, discretionary control that must be explicitly removed after the retention period, and nothing enforces that removal at exactly 7 years; it also lacks the automatic, permanent enforcement of a locked time-based retention policy. Configuring a lifecycle policy to move blobs to Archive after 30 days is valid from a cost perspective, but because the legal hold cannot protect against overwrite, the overall solution does not meet the stated need for both deletion and modification protection for 2,555 days.
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
About these practice questions
This AZ-305 question is part of Courseiva's 212-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 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-305 exam.