How to Rehydrate an Archive Blob with High Priority in Azure
A team moved blob data to the Archive tier to minimize cost. They now need to restore a few files for an audit. Which two statements are true about accessing archived blobs? Select two.
⚠ Common exam trap
A common mix-up: candidates assume archived blobs can be read immediately or that tier changes are instant, confusing the Archive tier's offline state with the online Cool or Hot tiers.
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
✓
Rehydration is required before the blob can be read or copied.
Archived blobs are in an offline state and cannot be read or copied directly. They must first be rehydrated to an online tier (Hot or Cool) through a process that changes the blob's tier or copies it to a new online blob. This rehydration process is asynchronous and takes time, depending on the priority set.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Archived blobs can be read immediately through normal blob reads.
Why it's wrong here
Because archive storage is deliberately offline, a normal blob read request will not return the blob's content immediately. Instead, the service will respond with an HTTP 409 error (condition BlobArchived), signaling that rehydration is required first. Only after rehydration is complete will standard read operations succeed.
When this WOULD be correct
If the question were about blobs in the Cool or Hot access tier, then normal blob reads would work immediately without rehydration.
- ✓
Rehydration is required before the blob can be read or copied.
Why this is correct
Archive blobs are stored offline, so their data content is not accessible on standard storage nodes. Any read or copy operation that accesses the blob's content — such as a download, Get Blob, or Copy Blob — will fail with an archive-related error until rehydration has been performed. Rehydration moves the blob back to an online tier, making it readable or copyable.
- ✓
Rehydration can target Hot or Cool access tier.
Why this is correct
When you initiate rehydration via the Set Blob Tier or Copy Blob operation, you can explicitly set the destination tier to either Hot or Cool, depending on projected access frequency. Hot is best for data expected to be accessed frequently, while Cool is more cost-effective for occasional reads. This flexibility allows you to balance latency and storage cost after archive retrieval.
- ✗
Archive tier provides the fastest retrieval time.
Why it's wrong here
Archive has the slowest retrieval behavior of all access tiers because it is offline and requires a rehydration step lasting minutes to hours. Hot tier provides immediate read access, and Cool tier provides slightly higher latency than Hot but still online. Therefore, Archive is designed for long-term, infrequent access, not fast retrieval.
When this WOULD be correct
If the question asked 'Which tier provides the lowest storage cost for infrequently accessed data?' then Archive tier would be correct because it is the cheapest storage tier.
- ✗
Changing a blob from Archive to Hot completes instantly and synchronously.
Why it's wrong here
Tier changes from Archive to Hot are asynchronous, not instantaneous or synchronous. The Set Blob Tier call returns immediately with a success status, but the actual rehydration process runs in the background and can take minutes to hours depending on blob size and requested priority. The blob remains in the Archive tier until the background operation finishes, which means the data is not immediately available.
When this WOULD be correct
This option would be correct if the question asked about changing a blob between Hot and Cool tiers, as those tier changes are instantaneous and synchronous.
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-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓Rehydration is required before the blob can be read or copied.Correct answer▾
Why this is correct
Archive blobs are stored offline, so their data content is not accessible on standard storage nodes. Any read or copy operation that accesses the blob's content — such as a download, Get Blob, or Copy Blob — will fail with an archive-related error until rehydration has been performed. Rehydration moves the blob back to an online tier, making it readable or copyable.
✗Archived blobs can be read immediately through normal blob reads.Wrong answer — click to see why▾
Why this is wrong here
Archived blobs are offline and cannot be read directly; they must first be rehydrated to an online tier (Hot or Cool) before access is possible.
★ When this WOULD be the correct answer
If the question were about blobs in the Cool or Hot access tier, then normal blob reads would work immediately without rehydration.
Why candidates choose this
Candidates may assume that all blob tiers support immediate read access, not realizing that Archive is an offline tier requiring rehydration.
✗Archive tier provides the fastest retrieval time.Wrong answer — click to see why▾
Why this is wrong here
Archive tier has the slowest retrieval time (hours for standard rehydration), not the fastest. Hot tier provides immediate access.
★ When this WOULD be the correct answer
If the question asked 'Which tier provides the lowest storage cost for infrequently accessed data?' then Archive tier would be correct because it is the cheapest storage tier.
Why candidates choose this
Candidates may confuse 'Archive' with 'archival' speed or assume that the cheapest tier also offers fast retrieval, overlooking the trade-off between cost and access time.
✗Changing a blob from Archive to Hot completes instantly and synchronously.Wrong answer — click to see why▾
Why this is wrong here
Changing a blob from Archive to Hot requires rehydration, which can take up to 15 hours, so it does not complete instantly or synchronously.
★ When this WOULD be the correct answer
This option would be correct if the question asked about changing a blob between Hot and Cool tiers, as those tier changes are instantaneous and synchronous.
Why candidates choose this
Candidates may confuse the instant tier change between Hot and Cool with the Archive tier, assuming all tier changes are immediate.
Analysis generated from the official AZ-104blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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
Learn chapter
Blob Lifecycle Management Policies
Key term
Audit
An audit is a systematic, independent review of IT systems, processes, and controls to verify compliance with policies, standards, and regulations.
Key term
Archive tier
Archive tier is an ultra-low-cost Azure Blob Storage access tier designed for long-term retention of data that is rarely accessed and can tolerate hours of retrieval latency.
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Same concept, more angles
8 more ways this is tested on AZ-104
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. A blob was moved to the Archive tier last month. A user now needs to open the file within a few hours. What should the administrator do first?
easy- A.Download the blob directly from the Archive tier
- ✓ B.Change the blob to Hot or Cool and wait for rehydration to complete
- C.Create a snapshot of the blob and open the snapshot instead
- D.Enable versioning on the storage account
Why B: Blobs in the Archive tier are offline and cannot be read directly. To access the data, you must first change the blob's access tier to Hot or Cool, which initiates a rehydration process that makes the blob available for reading. Since the user needs the file within a few hours, rehydration typically completes within that timeframe (up to 15 hours for Archive to Cool/Hot).
Variation 2. A blob was moved to the Archive tier last month. A project team now needs the file available later today, and they expect to read it several times during review. What should the administrator do first?
medium- A.Copy the blob directly from Archive to a local machine and reopen it there.
- ✓ B.Start a rehydration request and move the blob to the Hot tier with high priority.
- C.Change the blob to the Cool tier immediately and expect it to become available within minutes.
- D.Create a lifecycle rule to move the blob back to Hot automatically on the next day.
Why B: A blob in the Archive tier is offline and must be rehydrated (changed to Hot or Cool) before it can be accessed. Using high-priority rehydration ensures the blob becomes available within 1 hour, which meets the requirement for later today. The Hot tier is appropriate since the team expects to read the blob several times, providing low-latency access without incurring read costs from Cool tier.
Variation 3. A legal department archived a 120-GB blob three weeks ago. They now need the file available for review later today, and waiting more than a day would delay a court filing. What should the administrator do to make the blob readable as quickly as possible?
medium- A.Copy the blob to a new container and leave it in the Archive tier until the users need it.
- ✓ B.Start rehydration from Archive and choose High priority.
- C.Change the access tier from Archive directly to Cool and then download the blob immediately.
- D.Enable soft delete on the container and restore the blob from deleted items.
Why B: Rehydrating a blob from the Archive tier with High priority typically makes the blob readable within 1 hour, meeting the urgent same-day requirement. The Archive tier is offline, so the blob must be rehydrated (changed to an online tier like Hot or Cool) before it can be accessed. High-priority rehydration is designed for time-sensitive scenarios like this court filing deadline.
Variation 4. A legal team archived a 200-GB blob last quarter. They now need to open it repeatedly later today for review, and waiting more than a day would delay the case. Which two actions should the administrator take? Select two.
hard- ✓ A.Start a rehydration request and target the Hot tier.
- ✓ B.Set the rehydration priority to High.
- C.Copy the blob directly while it remains in the Archive tier.
- D.Change the blob back to the Archive tier after the request starts.
- E.Take a snapshot first and expect it to make the archived blob readable immediately.
Why A: Rehydrating a blob from the Archive tier to the Hot tier makes it accessible for frequent reads. The Hot tier is optimized for high-frequency access, which matches the legal team's need to open the blob repeatedly later today. Rehydration is the only way to change the blob's tier from Archive to an online tier like Hot.
Variation 5. An operations team archived monthly log exports six weeks ago. An auditor now needs one specific blob restored within a day, and the file will likely be opened several times during the audit. Which action should the administrator take first?
hard- A.Set the blob directly to the Archive tier again
- ✓ B.Rehydrate the blob to the Hot tier
- C.Create a snapshot of the archived blob and open the snapshot
- D.Increase the account redundancy to RA-GRS before the audit
Why B: The blob is currently in the Archive tier, which is offline and cannot be read directly. To access the data, the blob must first be rehydrated to an online tier (Hot or Cool) by changing its tier or copying it to a new blob. Rehydrating to the Hot tier ensures the blob is available for multiple reads within the audit timeframe, as the rehydration process typically takes up to 15 hours for Archive tier blobs.
Variation 6. A support engineer must download a blob that was moved to the Archive tier by a lifecycle rule. The file must be available as soon as possible for an investigation. What should the engineer do first?
medium- A.Download the blob directly from the Archive tier because archived blobs are always online.
- ✓ B.Change the blob's tier to Hot or Cool and wait for rehydration to complete.
- C.Move the blob to a different container in the same account to make it downloadable immediately.
- D.Disable the lifecycle rule so the blob becomes immediately readable again.
Why B: Blobs in the Archive tier are offline and must be rehydrated to a Hot or Cool tier before they can be accessed. Rehydration can take up to 15 hours, but setting the tier to Hot or Cool initiates the process, making the blob available as soon as possible for investigation.
Variation 7. A support engineer finds a blob that was moved to the Archive tier by a lifecycle rule and must download it today. Which two actions are required before the blob can be read? Select two.
easy- ✓ A.Change the blob access tier from Archive to Hot or Cool.
- ✓ B.Wait until the rehydration operation finishes.
- C.Download the blob directly from Archive without any tier change.
- D.Disable the lifecycle management policy for the storage account.
- E.Create a new container and copy the archived blob into it.
Why A: A blob in the Archive tier is offline and cannot be read directly. You must change its access tier to Hot or Cool (a process called rehydration) to make it available for download. This tier change initiates an asynchronous operation that moves the blob from the archived state to an online tier.
Variation 8. Quarterly invoices were moved to the Archive tier by a lifecycle rule. An auditor now needs one specific blob available for download within the next hour. What should the administrator do?
hard- A.Change the lifecycle rule so the blob will automatically move back to Hot on the next run.
- B.Set the blob directly to the Hot tier and download it immediately.
- ✓ C.Start a high-priority rehydration of the blob to the Hot tier, then wait for completion before downloading.
- D.Copy the archived blob to another container by using the portal copy command.
Why C: Blobs in the Archive tier are offline and must be rehydrated to an online tier (Hot or Cool) before they can be accessed. A high-priority rehydration completes within one hour, meeting the auditor's deadline. Changing a lifecycle rule (A) or directly setting the tier (B) does not initiate the necessary rehydration process, and copying an archived blob (D) fails because the blob is offline.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 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-104 exam.