Resize Azure VM Disks

Shrink OS Disk

Prereqs

• Must have Powershell AZ Module installed.
• Must have a windows based Azure VM

Steps

• RDP into VM
• Open Computer Management
• Open Disk Management
• Check the amount of free space on the Disk containing your C: drive and make note of the disknumber
• Open Powershell as an Administrator
• Run the following command

Get-Partition -DiskNumber <disknumber>

• Make note of partition containing your C: drive and run the following command choose a size that will make the entire disk smaller than an option in Azure
  • Here I'm resizing to 32GB and leaving room for the System Reserved partition on the same disk

Get-Partition -DiskNumber <disknumber> -PartitionNumber <partitionnumber> | Resize-Partition -Size 31GB

• Edit the variables at the top of the Shrink-VM-OSDisk.ps1 script
  • $DiskID
    • Click on Disks
    • Click on the OS Disk
    • Click on Properties
    • Copy entire Resource ID
  • $VMName
  • $DiskSizeGB
  • $AzSubscription
    • Name of your Azure Subscription
  • $Encrypted
    • $True or $False
    • If $True VM will need to be running and you will be prompted to confirm the removal of the Disk Encryption extension and to disable encryption. After resize you can manually reenable.
• Make sure you are connected with the Connect-AzAccount command
• Run Shrink-VM-OSDisk.ps1 script
• Once complete login to the VM and using Disk Managment extend the C: drive to take up any remaining space.