12 | November | 2014 | TroubleshootingSQL

In the last post of this series, I had talked about how to determine the number of page blobs present in a particular storage account and if the limit for Azure storage service will be exceeded based on the current configuration. In this post, I shall talk about something a bit closer to your virtual machine which is running the SQL Server workload. The script shown below will determine the IOPS supported by the data disks attached to the virtual machine and determine if all the data disks belong to the same storage account. It is recommended that your data disks belong to a single Azure storage account. If they are not part of the same storage account, then a warning in flagged in the output as seen in the screenshot.

The first part of the PowerShell script is uses Get-AzureVM cmdlet to find out the details of the Azure virtual machine which is running your workload. The output of this cmdlet is used as an input for the Get-AzureDataDisk cmdlet which allows me to find out all the data disks that are attached to my Azure virtual machine. Then a simple calculation lets me understand how much I/O workload the virtual machine can handle.

The next part of the script performs an important task of determining if the data disks attached to the virtual machine belong to the same storage account. If not, then it flags a warning. Typically, for high performance VMs, it is recommended that a single storage account be used for hosting the data disks of the virtual machine.

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


# Temporary variables

$AccountName = ""

$fail = 0

# Get the list of data disks for the Azure virtual machine

$DataDisks = Get-AzureVM -ServiceName "<Azure Service Name>" -Name "<Azure VM Name>" | Get-AzureDataDisk

Write-Host "INFO: This virtual machine has" $DataDisks.Count "data disks which can support a total of"($DataDisks.Count*500)" IOPS" -ForegroundColor Green

# Check if there is a data disk which belongs to a different storage account

foreach ($disk in $DataDisks)

{

if ($AccountName -eq "")

{

$AccountName = $disk.MediaLink.AbsoluteUri.Substring(8,$disk.MediaLink.AbsoluteUri.IndexOf(".")-8)

}

if ($AccountName -ne $disk.MediaLink.AbsoluteUri.Substring(8,$disk.MediaLink.AbsoluteUri.IndexOf(".")-8))

{

$fail = 1

}

}

# Show a warning if the data disks span across multiple storage accounts

if ($fail -eq 1)

{

Write-Host "WARNING: Mulitple storage accounts found for disks attached to the virtual machine" -ForegroundColor Red

}

else

{

Write-Host "PASSED: All disks attached to the virtual machine belong to a single storage account" -ForegroundColor Green

}