When I looking for monitoring the Windows based VM Disk Usage report,I came across the solution using PowerCLI,well lastest RVtools version does the same but it will pull all the VM disk usage not the specific VM.Using VMware tools + powercli you can able to pull the disk usage of Windows or Unix VM.

PowerCLI Script:

#Credits to Alan http://www.virtu-al.net/
#Modified by Deepak
#Prequisties need VMware Tools in VM to monitor the Disk
$vc= ‘192.168.1.6’
$vcuser=”root”
$vcpass=”kolaveri”
#Connecting the VC
Connect-VIServer -Server $vc -User $vcuser -Password $vcpass
$DiskUtil = @()
#Collecting all VM in VC
$AllVMs = Get-View -ViewType VirtualMachine -Filter @{“Name” = “do*”}
#Inplace “Do” we need to mention “MT”
$SortedVMs = $AllVMs | Select *, @{N=”NumDisks”;E={@($_.Guest.Disk.Length)}} | Sort-Object -Descending NumDisks
ForEach ($VM in $SortedVMs){
$Details = New-object PSObject
$Details | Add-Member -Name Name -Value $VM.name -Membertype NoteProperty
$DiskNum = 0
Foreach ($disk in $VM.Guest.Disk){
$Details | Add-Member -Name “Disk$($DiskNum)path” -MemberType NoteProperty -Value $Disk.DiskPath
$Details | Add-Member -Name “Disk$($DiskNum)Capacity(GB)” -MemberType NoteProperty -Value ([math]::Round($disk.Capacity/ 1GB))
$Details | Add-Member -Name “Disk$($DiskNum)FreeSpace(GB)” -MemberType NoteProperty -Value ([math]::Round($disk.FreeSpace / 1GB))
$DiskNum++
}
$DiskUtil += $Details
}
$DiskUtil | Export-Csv DiskUtil.csv

Credits goes to PowerCli Guru Alan and LucD