Expand the OS Drive on your Azure Resource Manager VM

This can be done via the portal by simply Stop and Deallocate the system and then select the drive and choose a larger size.

To script this via PowerShell you can do the following:

A bit more information on following the instructions from Microsoft found here.

  • Sign-in to your Microsoft Azure account in resource management mode and select your subscription as follows:

This will pop up the Azure Login window show below

After successfully entering my account information I see:

λ  Login-AzureRmAccount

Environment           : AzureCloud  
Account               : StevenTCramer@xxx.com  
TenantId              : xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx  
SubscriptionId        : xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx  
SubscriptionName      : Visual Studio Enterprise  
CurrentStorageAccount :  

You can see the SubscriptionName above: But to get a list of subscriptions you can use Get-AzureRmSubscription

  • To Change the subscription:
Select-AzureRmSubscription –SubscriptionName 'my-subscription-name'  
  • Set your resource group name and VM name as follows:
$rgName = 'my-resource-group-name'
$vmName = 'my-vm-name'

To get a list of you resource groups use Get-AzureRmResourceGroup. To get list of your Azure VMs use Get-azureRMVM

  • Obtain a reference to your VM as follows:
$vm = Get-AzureRmVM -ResourceGroupName $rgName -Name $vmName
  • Stop the VM before resizing the disk as follows:
 Stop-AzureRmVM -ResourceGroupName $rgName -Name $vmName


λ  Stop-AzureRmVM -ResourceGroupName $rgName -Name $vmName

Virtual machine stopping operation  
This cmdlet will stop the specified virtual machine. Do you want to continue?  
[Y] Yes  [N] No  [S] Suspend  [?] Help (default is "Y"): Y

OperationId :  
Status      : Succeeded  
StartTime   : 1/15/2017 11:49:08 AM  
EndTime     : 1/15/2017 11:51:31 AM  
Error       :  
  • And here comes the moment we’ve been waiting for! Set the size of the OS disk to the desired value and update the VM as follows:
$vm.StorageProfile.OSDisk.DiskSizeGB = 1023
Update-AzureRmVM -ResourceGroupName $rgName -VM $vm


λ  $vm.StorageProfile.OSDisk.DiskSizeGB = 1023
λ  Update-AzureRmVM -ResourceGroupName $rgName -VM $vm

RequestId IsSuccessStatusCode StatusCode ReasonPhrase  
--------- ------------------- ---------- ------------
                         True         OK OK
  • Updating the VM may take a few seconds. Once the command finishes executing, restart the VM as follows:
Start-AzureRmVM -ResourceGroupName $rgName -Name $vmName

Open the VM and start DiskManagment application then right click on the drive and then choose extend.

Steven T. Cramer

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Ada, Ohio