Having run into a few 'high ready time' alerts recently, and suffering through a perceived lack of performance on a number of VM's, I ran through our datacentre's to see if I could find any wasteful VM's. These had been assigned 2 or 4 vCPU's and were doing nothing with them, due mostly to client requirements and/or specifications. Dropping these down to use less vCPU’s actually made some of the VM’s faster.
Result.
Function Get-UnderUsedVM($VCServer,$FQDNCSVLocation)
#Finds all VM's with 'idle' vCPU's, that could be downgraded to less vCPU assigned
{
$VC = Connect-VIServer $VCServer
$Results = @()
$DCName = Get-Datacenter | Sort-Object
ForEach ($DC in $DCName)
{
$ClusterName = Get-Datacenter -Name $DC.Name | get-cluster | Sort-Object
Foreach ($ClusterEntity in $ClusterName)
{
$StatVM = get-cluster -Name $ClusterEntity | get-vm | Sort-Object
ForEach ($VM in $StatVM)
{
$Adatarow = "" | Select Datacenter,'Cluster Name','VM Name','Assigned CPUs','CPU Used',MhzPerCPU
$Adatarow.Datacenter = $DC.Name
$VMView = get-vm -Name $VM | get-view
$Adatarow.'Cluster Name' = $ClusterEntity
$Adatarow.'VM Name' = $VMView.Name
$Adatarow.'Assigned CPUs' = $VMView.Config.Hardware.NumCPU
$Adatarow.'CPU Used' = $VMView.Summary.QuickStats.OverallCpuUsage
$Adatarow.MhzPerCPU = [int]$VMView.Summary.QuickStats.OverallCpuUsage / $VMView.Config.Hardware.NumCPU
$Results += $ADataRow
}
}
}
$Results | Select Datacenter,'Cluster Name','VM Name','Assigned CPUs','CPU Used',MhzPerCPU | Where { $_.'Assigned CPUs' -gt 1} | Where { $_.MhzPerCPU -lt 1000} | export-csv $FQDNCSVLocation -notype
}
If you can make it run faster, have any suggestions, or had this help you please leave a comment below.
