How to Rehydrate Azure Archive Blobs to Hot, Cool, or Cold
Archive blobs are offline
Section titled "Archive blobs are offline"An Azure blob in Archive cannot be read or modified. Changing a label in the portal does not make it instantly available. Azure has to rehydrate the data into an online tier.[1]
There are two methods:
- Change the existing blob's tier with Set Blob Tier.
- Copy the archived blob into a new blob on Hot, Cool, or Cold.
The right method depends on retention rules, versions, lifecycle policies, and whether the original archived object must remain untouched.
Standard and high priority
Section titled "Standard and high priority"Standard priority processes requests in the order Azure receives them. Microsoft says objects under 10 GB may take up to 15 hours.
High priority costs more and may complete in under one hour for objects under 10 GB. You can raise an active request from Standard to High, but you cannot lower it again.
Those times are not a promise for a whole account. Rehydration throughput is limited at the storage-account level, not granted independently to every blob. A large batch can take much longer than the small-object estimate.
Batch requests instead of flooding the account
Section titled "Batch requests instead of flooding the account"Microsoft recommends batching rehydration requests. That makes progress easier to observe and reduces the chance that account-level throughput turns one emergency restore into a queue of thousands of competing objects.
Start with the files needed first. Confirm that they reach the online tier and can be read before requesting the rest.
Versions and snapshots need a copy
Section titled "Versions and snapshots need a copy"Snapshots and previous blob versions cannot be rehydrated in place. Copy them into a new online blob.
This matters during a recovery. The version you need may not be the current object. Check version and snapshot identifiers before assuming that Set Blob Tier will recover it.
Copying can avoid two traps
Section titled "Copying can avoid two traps"Changing the same archived blob to an online tier before the Archive minimum duration ends can create an early deletion charge. Copying it into a new online blob leaves the archived source in place and can avoid that specific fee.
A copy can also protect against an old lifecycle rule. Rehydrating the same blob does not necessarily make its last-modified date new. A policy based on age may move it back to Archive. A new copy has a new object history that is easier to reason about.
Check current Azure prices before choosing a method. Storage, retrieval, read operations, high-priority rehydration, and early deletion can all affect the bill.[2]
Where Blober fits
Section titled "Where Blober fits"Blober can apply a tier change to selected Azure blobs without a PowerShell loop. Azure still controls the rehydration queue and timing.
For a recovery, select a small batch, request the destination tier, wait for Azure to complete it, and open representative files. A status change is useful. A readable file is the real test.
Related Guides
Section titled "Related Guides"- How to Bulk Change Azure Blob Storage Access Tiers
- Azure Blob Tiers vs S3 Storage Classes
- Cloud Storage Ingress vs Egress Fees Explained
- Azure Blob Storage Setup and Transfers
Get Blober
Section titled "Get Blober"Blober applies tier changes to the blobs you select, without a PowerShell loop. Azure still controls the rehydration queue, so plan the wait and verify the files afterwards.