Credit where credit is due, first of all. This post would not be possible without HEAVILY (and by heavily I mean stealing everything but a single parameter modification) referencing https://webmakers.co.nz/how-to-convert-entire-data-in-a-blob-storage-from-cool-storage-tier-into-archive-access-tier/, so please go check that out so he gets the credit. 

Feel free to now skip to “The Command” if you don’t want the explanation of how I got here and why it works.

Backstory

We setup Azure storage and put a metric ton of data into it, organized into folders. Unfortunately, our cost projections were way off and we were bleeding money to Microsoft for the storage. This is a byproduct of our first foray into storing data natively in Microsoft Blobs on this scale. We were able to change the storage type to minimize this cost a lot, but knew that modifying the AccessTier on a subset of the data that is not regularly accessed would bring us back to the ballpark we expected.

We have two containers, lets call them data1 and data2, each with subfolders within subfolders within subfolders. We did not have this organized so that one container could be “cool” storage and one “hot”. All Containers were set to “Hot”, and we needed a single root “folder” (I’ll explain the quotes in a minute under The Breakthrough) within a container changed to cool, while the others remained hot.

Issue

You can modify the AccessTier on an entire container, or a single “file”, but not on a folder of files. Or so it seemed like from everything we were seeing (and the command provided in https://webmakers.co.nz/how-to-convert-entire-data-in-a-blob-storage-from-cool-storage-tier-into-archive-access-tier/ (seriously, click on that and give my source a reference). Additionally the folders turned out to not be anything usable to filter the selection.

The Breakthrough

In troubleshooting another issue I was having in getting powershell to load the right modules and run them correctly, I stumbled on a comment in a post about the “folders” in containers and blobs. It tickled something in my brain, but didn’t click all the way into place yet. I wish I still had that page open, but seeing as I read through 30 or more posts about this, I doubt I’ll ever find it again to reference it. My deepest apologies, and I promise I will edit this if I find it.

What it explained is that the folders are not folders in the traditional Microsoft Windows sense. Blob storage is a flat file system. The folders are just the filenames, and Azure parses them into displaying them into folders. So in collection “data” there is rootfolder\subfolder\file.txt, that is an actual file name. If windows handled files this way, and you wanted to use a command prompt to “cd” (change directory) into the users directory, it wouldn’t work.

I hope that makes sense.

The command

All that explanation aside, below is the command modified to pull only files from RootFolder1 and change them to the “cool” tier. If you had RootFolder2 and RootFolder3, they would remain the Access Tier they currently are. Items in bold need to be from your account.

Install-Module -Name AzureRM
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned
Import-Module AzureRM
$StgAcc = “YourStorageAccountName”
$StgKey = “YourConnectionKey”
$Container = “YourContainerName”
$ctx = New-AzureStorageContext -StorageAccountName $StgAcc -StorageAccountKey $StgKey
Connect-AzureRmAccount
$blob = Get-AzureStorageBlob -Container $Container -Context $ctx -blob RootFolder1*
$blob.icloudblob.setstandardblobtier("Cool")

*after “Connect-AzureRmAccount” you will be prompted for a username and password to connect to Azure.

Recommendation:

After line 9, you can enter $blob to see what is stored in that variable. I did this to ensure it only pulled the files I wanted to change. It also shows the AccessTier. I ran it again after line 10 to verify the AccessTier changed.

Second Example:

If you want to make changes on a subfolder of a root folder, or a folder four levels deep, the modification is just to the -blob parameter. Say in “YourContainerName” there is folder strucure “RootFolder1\subfolder1\sub subfolder\” you would modify the -blob parameter as follows (note that the folder structure has a space, so requires the quotes:

Install-Module -Name AzureRM
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned
Import-Module AzureRM
$StgAcc = “YourStorageAccountName”
$StgKey = “YourConnectionKey”
$Container = “YourContainerName”
$ctx = New-AzureStorageContext -StorageAccountName $StgAcc -StorageAccountKey $StgKey
Connect-AzureRmAccount
$blob = Get-AzureStorageBlob -Container $Container -Context $ctx -blob "RootFolder1/subfolder1/sub subfolder/*"
$blob.icloudblob.setstandardblobtier("Cool")

Additional helpful notes, maybe

YourStorageAccountName  – open the Azure portal and go to “storage accounts”. the “Name” of the accounts your containers are in is what is used here.
YourConnectionKey  – once you have your storage account open, go to “Access Keys” under settings, this is the super long and complicated string under “Key”
YourContainerName – same page you are already on, scroll down to “container” under Blob Service. This will be the “Name” that contains the data that you want to work with.

The Saga is Complete

And with that I will go home, plug in my computer and let powershell change the AccessTier of a couple thousand files while I get some food and melt my brain with junk TV shows.