#requires -version 3.0

Function Get-VHDSummary {

<#
.Synopsis
Get Hyper-V VHD Information
.Description
Get a summary report of all associated VHDs with their respective virtual
machines. This requires the Hyper-V PowerShell module.
.Example
PS C:\> Get-VHDSummary

VMName     : CHI-Client02
Path       : D:\VHD\Win7_C.vhd
Type       : Dynamic
Format     : VHD
SizeGB     : 25
FileSizeGB : 21

VMName     : CHI-Client02
Path       : C:\Users\Public\Documents\Hyper-V\Virtual Hard Disks\CHI-Client2-Swap.vhdx
Type       : Dynamic
Format     : VHDX
SizeGB     : 4
FileSizeGB : 1

VMName     : Win2012-01
Path       : D:\VHD\Win2012-01_340B1F8F-FFFB-4DCD-9B3A-7819D8BCE3C2.avhdx
Type       : Differencing
Format     : VHDX
SizeGB     : 40
FileSizeGB : 2

.Example
PS C:\> get-vhdsummary | sort Type | format-table -GroupBy Type -Property VMName,Path,*Size*
.Example
PS C:\> get-vhdsummary | Copy-item -destination Z:\VHDBackup
.Example
PS C:\> get-vhdsummary | measure-object -property FilesizeGB -sum
.Link
Get-VM
Get-VHD
#>

Param()

Get-VM  | Select-Object -expandproperty harddrives | 
Select-Object -property VMName,Path,
@{Name="Type";Expression={(Get-VHD -Path $_.Path).VhdType}},
@{Name="Format";Expression={(Get-VHD -Path $_.Path).VhdFormat}},
@{Name="SizeGB";Expression={((Get-VHD -Path $_.Path).Size)/1GB -as [int]}},
@{Name="FileSizeGB";Expression={((Get-VHD -Path $_.Path).FileSize)/1GB -as [int]}}

} #end function

<#
This is a variation that is more efficient and a better PowerShell function.
#>
Function Get-VHDSummary2 {
Param()

#get all virtual machines
$vms=Get-VM

foreach ($vm in $vms) {
  Write-Host "Getting drive info from $($vm.name)" -foregroundcolor Cyan
  #get the hard drives foreach virtual machine
  $vm.HardDrives | ForEach-Object {
      #a VM might have multiple drives so for each one get the VHD
      $vhd=Get-VHD -path $_.path

      <#
       $_ is the hard drive object so select a few properties and
       include properties from the VHD
      #>
      $_ | Select-Object -property VMName,Path,
        @{Name="Type";Expression={$vhd.VhdType}},
        @{Name="Format";Expression={$vhd.VhdFormat}},
        @{Name="SizeGB";Expression={($vhd.Size)/1GB -as [int]}},
        @{Name="FileSizeGB";Expression={($vhd.FileSize)/1GB -as [int]}}
 } #foreach
} #foreach vm

} #close function