Here is a script that will show you 3 things per host:
1. vCPU:pCPU ratio,
2. Host Memory Granted,
3. Host Memory Used.
It will count all the vCPUs on a host and the (physical) pCPUs, the vCPU differed by pCPU is the ratio. The vCPU:pCPU should in my opinion be:
High CPU load environment <4:1
Medium CPU load environment ~4:1
Low CPU load environment >4:1
The “Host Memory Granted” percentage value is the sum of all VM granted memory compared to the total host memory, you can also call this Worst-Case usage. The “Host Memory Used” percentage is the real value of the host used memory.
“Host Memory Granted” should be <90% unless you know what you are doing.
"Host Memory Used" should be <80% depending on the cluster size (see Duncan’s HA Deep Dive).
$TotalNumvCPUs = 0
Foreach ($Cluster in (Get-Cluster |Sort Name)){
$HostNumvCPUs = 0
$HostNumvMem = 0
$array = @();
Foreach ($ESXHost in ($Cluster |Get-VMHost |Sort Name)){
Foreach ($VM in ($ESXHost |Get-VM)){ # or only powered on, Foreach ($VM in ($ESXHost |Get-VM| Where-Object {$_.PowerState -eq "PoweredOn"})){
$HostNumvCPUs += ($VM).NumCpu
$HostNumvMem += "{0:N0}" -f ($VM).MemoryGB
}
$HostCPUratio = "{0:N0}" -f ($HostNumvCPUs / ($ESXHost).NumCpu)
$HostMemUsable = "{0:N0}" -f (($ESXHost | Get-View).Hardware.MemorySize/1GB)
$HostGrantedMem = "{0:N0}" -f ($HostNumvMem/$HostMemUsable*100)
$HostUSageMem = "{0:N0}" -f (($ESXHost).MemoryUsageGB/$HostMemUsable*100)
$HostVar = @{cluster=$($Cluster.name); host=$($ESXHost.name); HostCPURatio=$HostCPUratio + ":1"; HostMemGranted=$HostGrantedMem + "%"; HostMemUsed=$HostUSageMem + "%"}
$Newobject = New-Object PSObject -Property $HostVar
$array += $Newobject
$TotalNumvCPUs += $HostNumvCPUs
$TotalNumvMem += $HostNumvMem
$HostNumvCPUs = 0
$HostNumvMem = 0
}
$array | Select-Object cluster,host,HostCPURatio,HostMemGranted,HostMemUSed | Format-Table -AutoSize
$TotalNumvCPUs = 0
$TotalNumvMem = 0
}
Output:
