Attach a data disk to a Windows VM with PowerShell

• 10/16/2018
• 3 minutes to read
• Contributors
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This article shows you how to attach both new and existing disks to a Windows virtual machine by using PowerShell.

First, review these tips:

• The size of the virtual machine controls how many data disks you can attach. For more information, see Sizes for virtual machines.
• To use Premium storage, you'll need a Premium Storage-enabled VM type like the DS-series or GS-series virtual machine. For more information, see Premium Storage: High-Performance Storage for Azure Virtual Machine Workloads.

Launch Azure Cloud Shell

The Azure Cloud Shell is a free interactive shell that you can use to run the steps in this article. It has common Azure tools preinstalled and configured to use with your account. Just click the Copy to copy the code, paste it into the Cloud Shell, and then press enter to run it. There are a few ways to launch the Cloud Shell:

Click Try It in the upper right corner of a code block.
Open Cloud Shell in your browser.
Click the Cloud Shell button on the menu in the upper right of the Azure portal.

To install and use the PowerShell locally, this tutorial requires the Azure PowerShell module version 6.0.0 or later. Run Get-Module -ListAvailable AzureRM to find the version. If you need to upgrade, see Install Azure PowerShell module. If you are running PowerShell locally, you'll also need to run Connect-AzureRmAccount to create a connection with Azure.

Add an empty data disk to a virtual machine

This example shows how to add an empty data disk to an existing virtual machine.

Using managed disks

$rgName = 'myResourceGroup'
$vmName = 'myVM'
$location = 'East US' 
$storageType = 'Premium_LRS'
$dataDiskName = $vmName + '_datadisk1'

$diskConfig = New-AzureRmDiskConfig -SkuName $storageType -Location $location -CreateOption Empty -DiskSizeGB 128
$dataDisk1 = New-AzureRmDisk -DiskName $dataDiskName -Disk $diskConfig -ResourceGroupName $rgName

$vm = Get-AzureRmVM -Name $vmName -ResourceGroupName $rgName 
$vm = Add-AzureRmVMDataDisk -VM $vm -Name $dataDiskName -CreateOption Attach -ManagedDiskId $dataDisk1.Id -Lun 1

Update-AzureRmVM -VM $vm -ResourceGroupName $rgName

Using managed disks in an Availability Zone

To create a disk in an Availability Zone, use New-AzureRmDiskConfig with the -Zone parameter. The following example creates a disk in zone 1.

$rgName = 'myResourceGroup'
$vmName = 'myVM'
$location = 'East US 2' 
$storageType = 'Premium_LRS'
$dataDiskName = $vmName + '_datadisk1'

$diskConfig = New-AzureRmDiskConfig -SkuName $storageType -Location $location -CreateOption Empty -DiskSizeGB 128 -Zone 1
$dataDisk1 = New-AzureRmDisk -DiskName $dataDiskName -Disk $diskConfig -ResourceGroupName $rgName

$vm = Get-AzureRmVM -Name $vmName -ResourceGroupName $rgName 
$vm = Add-AzureRmVMDataDisk -VM $vm -Name $dataDiskName -CreateOption Attach -ManagedDiskId $dataDisk1.Id -Lun 1

Update-AzureRmVM -VM $vm -ResourceGroupName $rgName

Initialize the disk

After you add an empty disk, you'll need to initialize it. To initialize the disk, you can sign in to a VM and use disk management. If you enabled WinRM and a certificate on the VM when you created it, you can use remote PowerShell to initialize the disk. You can also use a custom script extension:

    $location = "location-name"
    $scriptName = "script-name"
    $fileName = "script-file-name"
    Set-AzureRmVMCustomScriptExtension -ResourceGroupName $rgName -Location $locName -VMName $vmName -Name $scriptName -TypeHandlerVersion "1.4" -StorageAccountName "mystore1" -StorageAccountKey "primary-key" -FileName $fileName -ContainerName "scripts"

The script file can contain code to initialize the disks, for example:

    $disks = Get-Disk | Where partitionstyle -eq 'raw' | sort number

    $letters = 70..89 | ForEach-Object { [char]$_ }
    $count = 0
    $labels = "data1","data2"

    foreach ($disk in $disks) {
        $driveLetter = $letters[$count].ToString()
        $disk | 
        Initialize-Disk -PartitionStyle MBR -PassThru |
        New-Partition -UseMaximumSize -DriveLetter $driveLetter |
        Format-Volume -FileSystem NTFS -NewFileSystemLabel $labels[$count] -Confirm:$false -Force
    $count++
    }

Attach an existing data disk to a VM

You can attach an existing managed disk to a VM as a data disk.

$rgName = "myResourceGroup"
$vmName = "myVM"
$location = "East US" 
$dataDiskName = "myDisk"
$disk = Get-AzureRmDisk -ResourceGroupName $rgName -DiskName $dataDiskName 

$vm = Get-AzureRmVM -Name $vmName -ResourceGroupName $rgName 

$vm = Add-AzureRmVMDataDisk -CreateOption Attach -Lun 0 -VM $vm -ManagedDiskId $disk.Id

Update-AzureRmVM -VM $vm -ResourceGroupName $rgName

Next steps

Create a snapshot.