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:
Login-AzureRmAccount

This will pop up the Azure Login window show below

After successfully entering my account information I see:

λ  Login-AzureRmAccount

Environment           : AzureCloud
Account               : [email protected]
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

Output

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

Output

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.