Create a managed disk from a snapshot with PowerShell
This script creates a managed disk from a snapshot. Use it to restore a virtual machine from snapshots of OS and data disks. Create OS and data managed disks from respective snapshots and then create a new virtual machine by attaching managed disks. You can also restore data disks of an existing VM by attaching data disks created from snapshots.
If you don't have an Azure subscription, create an Azure free account before you begin.
Sample script
#Provide the subscription Id
$subscriptionId = 'yourSubscriptionId'
#Provide the name of your resource group
$resourceGroupName ='yourResourceGroupName'
#Provide the name of the snapshot that will be used to create Managed Disks
$snapshotName = 'yourSnapshotName'
#Provide the name of the Managed Disk
$diskName = 'yourManagedDiskName'
#Provide the size of the disks in GB. It should be greater than the VHD file size.
$diskSize = '128'
#Provide the storage type for Managed Disk. Acceptable values are Standard_LRS, Premium_LRS, PremiumV2_LRS, StandardSSD_LRS, UltraSSD_LRS, Premium_ZRS and StandardSSD_ZRS.
$storageType = 'Premium_LRS'
#Required for Premium SSD v2 and Ultra Disks
#Provide the Availability Zone you'd like the disk to be created in, default is 1
$zone=1
#Provide the Azure region (e.g. westus) where Managed Disks will be located.
#This location should be same as the snapshot location
#Get all the Azure location using command below:
#Get-AzLocation
$location = 'westus'
#Set the context to the subscription Id where Managed Disk will be created
Select-AzSubscription -SubscriptionId $SubscriptionId
$snapshot = Get-AzSnapshot -ResourceGroupName $resourceGroupName -SnapshotName $snapshotName
#If you're creating a Premium SSD v2 or an Ultra Disk, add "-Zone $zone" to the end of the command
$diskConfig = New-AzDiskConfig -SkuName $storageType -Location $location -CreateOption Copy -SourceResourceId $snapshot.Id -DiskSizeGB $diskSize
New-AzDisk -Disk $diskConfig -ResourceGroupName $resourceGroupName -DiskName $diskName
Performance impact - background copy process
When you create a managed disk from a snapshot, it starts a background copy process. You can attach a disk to a VM while this process is running but you'll experience performance impact (4k disks experience read impact, 512e experience both read and write impact). For Ultra Disks and Premium SSD v2, you can check the status of the background copy process with the Azure CLI. This isn't currently supported with the Azure PowerShell module.
Important
You can't use the following sections to get the status of the background copy process for disk types other than Ultra Disk or Premium SSD v2. Other disk types will always report 100%.
Script explanation
This script uses following commands to create a managed disk from a snapshot. Each command in the table links to command specific documentation.
| Command | Notes |
|---|---|
| Get-AzSnapshot | Gets snapshot properties. |
| New-AzDiskConfig | Creates disk configuration that is used for disk creation. It includes the resource Id of the parent snapshot, location that is same as the location of parent snapshot and the storage type. |
| New-AzDisk | Creates a disk using disk configuration, disk name, and resource group name passed as parameters. |
Next steps
Create a virtual machine from a managed disk
For more information on the Azure PowerShell module, see Azure PowerShell documentation.
Additional virtual machine PowerShell script samples can be found in the Azure Windows VM documentation.