Azure Storage and SQL Server – Part 2

In the first post of this series, I had talked about the cheat sheet which documents the best practices for storage for SQL Server workloads running on Azure Virtual Machines. In this post, I am going to show how to automate additional checks for your virtual machine and your storage configuration. I am going to show how to determine if you have more than 40 disks in the storage account as they would not be able to sustain more than 20,000 IOPs as per the storage limits for Azure storage accounts.

The first part of the PowerShell script is used to find out the number of page blobs available in the storage account using the Get-AzureStorageContainer cmdlet. This allows me to fetch all the containers in a particular storage account which is specified as a parameter in the beginning of the script. The storage account context was created using the New-AzureStorageContext cmdlet. This is required for all the subsequent commands to ensure that the cmdlet executes against the correct storage account. This is required especially if you have more than one storage account associated with your subscription.

The next part of the script uses Get-AzureStorageBlob cmdlet to determine the number of blobs in a container. I used a foreach loop to determine the contents of each container. The reason I am using local variables to ensure that I minimize the network call to the Azure Storage service to get the filtering for both types of blobs in the storage container.

The last if-else block determines if you have more than 40 disks in the storage account. If yes, then it flags off an issue because if all the disks are active, they will not be able to scale to their potential of 500 IOPS. This is due to the fact that 20,000 IOPS per storage account limit will be divided across the disks available in the storage account.

The Powershell script and a screenshot of the output is shown below.

# Assign the storage account name

$StorageAccount = "<storage account name>"

 # Get the storage account key as this is needed for creating the storage context

$StorageKey = Get-AzureStorageKey $StorageAccount | %{ $_.Primary }

 # Create a new storage context for use in the next sections on the code block

$StorageContext = New-AzureStorageContext -StorageAccountName $StorageAccount -StorageAccountKey $StorageKey

 # Find out all the containers in the storage account

$Containers = Get-AzureStorageContainer -Context $StorageContext

 # Local variables for tracking the page and block blobs

$PageBlob = 0

$BlockBlob = 0

 # Get the disks in each container and count each type of blog present for the summary output

foreach ($name in $Containers)


$temp = Get-AzureStorageBlob -Container $name.Name -Context $StorageContext

$Blob = $temp | Where-Object {$_.BlobType -eq "PageBlob"}

$PageBlob += $Blob.Count 

$Blob = $temp | Where-Object {$_.BlobType -eq "BlockBlob"}

$BlockBlob += $Blob.Count 


Write-Host "INFO: There are" $Containers.Count "containers in the storage account:" $StorageAccount "which have" $PageBlob "Page Blob(s) and" $BlockBlob "Block Blob(s)" -ForegroundColor Green

 # Determine if 20K IOPS limit will be crossed due to having 40+ disks

if ($PageBlob -le 40)


Write-Host "INFO: This storage account has" $PageBlob "disk(s) which can support a total of" ($PageBlob*500) "IOPS" -ForegroundColor Green




Write-Host "ISSUE: This storage account has" $PageBlob "disk(s) which can ONLY support a total of 20,000 IOPS" -ForegroundColor Red



Previous post in the series

Azure Storage and SQL Server – Part 1



Azure Storage

Azure Subscription and Service Limits, Quotas, and Constraints

* This blog post has been written based on the service details available on 9th November, 2014.