Is rehydration of the (Azure Blob Storage) archive tier always needed?

0
votes

I have studied the following link to understand the Hot, Cool and Archive tiers of Azure Storage V2.

https://docs.microsoft.com/en-us/azure/storage/blobs/storage-blob-storage-tiers

In the Blob rehydration section it says:

To read data in archive storage, you must first change the tier of the blob to hot or cool. This process is known as rehydration and can take up to 15 hours to complete.

My questions are:

  1. Can I get just list of all blobs without rehydration? Is it going to cost me?
  2. Do I have to perform rehydration before reading/deleting a single file?
  3. Do I have to perform rehydration to delete a file before 180 days?
1
azureazure-storageazure-storage-account

1 Answers

3
votes

All answers are taken from the article you linked to:

1) Yes, you can get a list and it will not cost you extra
2) Yes, you have to rehydrate to read file contents, but you can delete without rehydrating

While a blob is in archive storage, the blob data is offline and cannot be read, copied, overwritten, or modified. You can't take snapshots of a blob in archive storage. However, the blob metadata remains online and available, allowing you to list the blob and its properties. For blobs in archive, the only valid operations are GetBlobProperties, GetBlobMetadata, ListBlobs, SetBlobTier, and DeleteBlob.

As an addition to the answer to the reading part of question 2):

Blob-level tiering allows you to change the tier of your data at the object level using a single operation called Set Blob Tier. You can easily change the access tier of a blob among the hot, cool, or archive tiers as usage patterns change, without having to move data between accounts. All tier changes happen immediately. However, rehydrating a blob from archive can take several hours.

3) The 180 days are the minimum amount of time a blob needs to be in archive storage. Changes before that period incur an early deletion charge. This does not change the way you delete blobs, so you can still call DeleteBlob (and be charged the early deletion charge).

Any blob that is deleted or moved out of the cool (GPv2 accounts only) or archive tier before 30 days and 180 days respectively will incur a prorated early deletion charge.