windows

A couple of years ago I did a post on how to map your windows disk with the real disk in VMware. The post will be an extension of it but with updated commands.

Why do I need to know the mapping? It happens when you stumble upon a VM disk with many disks attached. If the many disks vary in size you normally can look at those numbers and match them with the disks in VMware, but when all disks have the same size that approach become difficult.

Windows serial number:

In windows, we can retrieve the serial number on the disk we need to expand and then map the serial number to the VMware disk. In newer Windows Server versions it’s fairly easy to find but when dealing with older than 2012 you are missing the PowerShell cmdlets like get-disk. Someone on StackOverflow got a way that works on Windows Server 2008 > 2022.

$DriveLetter = "C:"
Get-CimInstance -ClassName Win32_DiskDrive |
Get-CimAssociatedInstance -Association Win32_DiskDriveToDiskPartition |
Get-CimAssociatedInstance -Association Win32_LogicalDiskToPartition |
Where-Object DeviceId -eq $DriveLetter |
Get-CimAssociatedInstance -Association Win32_LogicalDiskToPartition |
Get-CimAssociatedInstance -Association Win32_DiskDriveToDiskPartition |
Select-Object -Property SerialNumber

VMware disk:

From VMware’s side, it’s straightforward to find the disk and its serial number. Below is an scripted way of finding the disk and then adding the extra capacity.

Connect-VIServer ""

$VMname = ""
$disksn = "6000c295ec128b3d14472bdbf8e65aee"
$vmDisk = (Get-VM $VMname | Get-HardDisk) | Where-Object {$_.ExtensionData.Backing.uuid.Replace("-","") -eq $disksn } 

$ExpandSizeGb = 50
$vmDisk | Set-HardDisk -CapacityGB ($vmDisk.CapacityGB + $ExpandSizeGb) -Confirm:$false 

Conclusion:

Instead of having to guess what disk in windows is mapping to the VMware disk you here have a more automated way. The disk serial number retrieve commands are compatible with up to Windows Server 2022.