How Are My VHD’s/Passthough Disk’s Connected To My Virtual Machine? - Taylor Brown's Blog - Site Home

Updated 2/23 – Added VHD File Size and Fixed a Few Bugs.

This is a follow up on my previous post on Hyper-V WMI: What VHD’s/Physical Disks Are Associated With a Virtual Machine?. I had been getting questions about how to better identify what disks are connected to what bus location/controller. Specifically I have been getting a lot of questions about how back up or copy just the VHD that the guest sees as drive letter C or D etc… I wrote a revised script that gives a bit more information specifically the controller addresses and the Instance ID of the controller. The reason that’s interesting is that you can determine that the C volume is on Disk Number 1 and that Disk Number 1 is connected to IDE Port 0/1 and on the parent you know that IDE Port 0/1 is backed by S:\vhds\foo.vhd well then you know what to backup… So what about SCSI controller’s? Well they are a bit more challenging but not to much – if you look at the PNP ID of the controller its VMBUS\<GUID> where the GUID is the same as the first GUID in the WMI instance id for the controller on the management OS (take a look at the screen capture below). Hopefully this is helpful – Enjoy!

Here’s the Script:

$HyperVParent = "localhost" 
$VMManagementService = Get-WmiObject -class "Msvm_VirtualSystemManagementService" -namespace "root\virtualization" -ComputerName $HyperVParent 


foreach ($vm in Get-WmiObject -Namespace root\virtualization -Query "Select * From Msvm_ComputerSystem where Description='Microsoft Virtual Machine'" -ComputerName $HyperVParent)
{     $VMSettingData = Get-WmiObject -Namespace "root\virtualization" -Query "Associators of {$Vm} Where ResultClass=Msvm_VirtualSystemSettingData AssocClass=Msvm_SettingsDefineState" -ComputerName $HyperVParent  
    $VirtualDiskResource = Get-WmiObject -Namespace "root\virtualization" `
        -Query "Associators of {$VMSettingData} Where ResultClass=Msvm_ResourceAllocationSettingData AssocClass=Msvm_VirtualSystemSettingDataComponent" `
        -ComputerName $HyperVParent | Where-Object { $_.ResourceSubType -match "Microsoft Virtual Hard Disk" } 
    
    $PhysicalDiskResource = Get-WmiObject -Namespace "root\virtualization" `
        -Query "Associators of {$VMSettingData} Where ResultClass=Msvm_ResourceAllocationSettingData AssocClass=Msvm_VirtualSystemSettingDataComponent" `
        -ComputerName $HyperVParent | Where-Object { $_.ResourceSubType -match "Microsoft Physical Disk Drive" } 
        
    if ($VirtualDiskResource -ne $null)
    {
        Write-Host "VHD Connections: "
        foreach ($i in $VirtualDiskResource)
        {
            Write-Host "  Virtual Hard Disk At: "  ([WMI]$i).Connection[0]
            Write-Host "  Virtual Hard Disk VHD Size: " (get-item ([WMI]$i).Connection[0]).Length
            Write-Host "  Virtual Hard Disk Connected To: " ([WMI]([WMI]$i.Parent).Parent).ElementName
            Write-Host "  Controller Index: " ([WMI]([WMI]$i.Parent).Parent).Address
            Write-Host "  Controller Instance ID: " ([WMI]([WMI]$i.Parent).Parent).InstanceID
            Write-Host "  Disk Location On Controller: " ([WMI]$i.Parent).Address
            Write-Host     
        }
    }
    
    if ($PhysicalDiskResource -ne $null)
    {
        Write-Host "Physical Disk Connections: "
        foreach ($i in $PhysicalDiskResource)
        {
            Write-Host "  Passthrough Disk At:"  ([WMI]$i.HostResource[0]).ElementName
            Write-Host "  Passthrough Disk Drive Number:  " ([WMI]$i.HostResource[0]).DriveNumber
            Write-Host "  Virtual Hard Disk Connected To: " ([WMI]$i.Parent).ElementName
            Write-Host "  Controller Index: " ([WMI]$i.Parent).Address
            Write-Host "  Controller Instance ID: " ([WMI]$i.Parent).InstanceID
            Write-Host "  Disk Location On Controller: " ([WMI]$i).Address
            Write-Host
        }
    }
}

Here’s the Output of the Script:

PS D:\> .\DiskAttachment2.ps1
VHD Connections:
Virtual Hard Disk At: C:\Users\Public\Documents\Hyper-V\Virtual hard disks\SERVER2008-ENT-64-6001.18000.080118-1840_amd64fre_ServerEnterprise_en-us_VL.vhd
Virtual Hard Disk Connected To: IDE Controller 0
Controller Index: 0
Controller Instance ID: Microsoft:4DA5F246-7501-49B3-AE41-B1B5B4FCF57F\83F8638B-8DCA-4152-9EDA-2CA8B33039B4\0
Disk Location On Controller: 0

Virtual Hard Disk At: C:\vhd\VHD on Local Storage.vhd
Virtual Hard Disk Connected To: IDE Controller 0
Controller Index: 0
Controller Instance ID: Microsoft:4DA5F246-7501-49B3-AE41-B1B5B4FCF57F\83F8638B-8DCA-4152-9EDA-2CA8B33039B4\0
Disk Location On Controller: 1

Virtual Hard Disk At: S:\Vhds\VHD on LUN.vhd
Virtual Hard Disk Connected To: SCSI Controller
Controller Index:
Controller Instance ID: Microsoft:4DA5F246-7501-49B3-AE41-B1B5B4FCF57F\B090A115-B8E6-4706-BE6C-C8ECDDC4A90B\0
Disk Location On Controller: 1

Virtual Hard Disk At: S:\Vhds\Disk on SCSI 2.vhd
Virtual Hard Disk Connected To: SCSI Controller
Controller Index:
Controller Instance ID: Microsoft:4DA5F246-7501-49B3-AE41-B1B5B4FCF57F\87617569-E20C-4982-AC44-04A4251C82BA\0
Disk Location On Controller: 0

Physical Disk Connections:
Passthrough Disk At: Disk 3
Passthrough Disk Drive Number: 3
Virtual Hard Disk Connected To: SCSI Controller
Controller Index:
Controller Instance ID: Microsoft:4DA5F246-7501-49B3-AE41-B1B5B4FCF57F\B090A115-B8E6-4706-BE6C-C8ECDDC4A90B\0
Disk Location On Controller: 0

Here’s a Screen Capture Of the PNP ID in the Guest:

Taylor Brown
Hyper-V Integration Test Lead
http://blogs.msdn.com/taylorb