Virtualisation Tips & Tricks

If you use the vSphere UI to configure individual virtual disk I/O shares or limits for a Virtual Machine, it looks like this functionality has been removed in vSphere 8.x in favor of using VM Storage Policies, which has been around for almost a decade now.

If you still wish to manage the SIOC configurations on an VM basis, you can use the StorageIOAllocationInfo vSphere API property on a virtual disk is and here is a quick PowerCLI snippet that demonstrates using the vSphere API to configure a limit for a virtual disk with the label “Hard disk 2” as an example.

-1 means that the limits have been removed altogether! The so called unlimited.

$vmName = "Delfins_WEB-pVxc"
$vmDiskName = "Hard disk 2”
$diskLimit = -1
 
### DO NOT EDIT BEYOND HERE ###
 
$vm = Get-VM $vmName
$disk = ($vm | Get-HardDisk) | where {$_.Name -eq $vmDiskName}
 
$spec = New-Object VMware.Vim.VirtualMachineConfigSpec
$spec.DeviceChange = New-Object VMware.Vim.VirtualDeviceConfigSpec[] (1)
$spec.DeviceChange[0] = New-Object VMware.Vim.VirtualDeviceConfigSpec
$spec.DeviceChange[0].Device = $disk.ExtensionData
$spec.DeviceChange[0].Device.Key = $disk.ExtensionData.key
$spec.DeviceChange[0].Device.UnitNumber = $disk.ExtensionData.UnitNumber
$spec.DeviceChange[0].Device.ControllerKey = $disk.ExtensionData.ControllerKey
$spec.DeviceChange[0].Device.Backing = $disk.ExtensionData.Backing
$spec.DeviceChange[0].Device.StorageIOAllocation = $disk.ExtensionData.StorageIOAllocation
$spec.DeviceChange[0].Device.StorageIOAllocation.Limit = $diskLimit
$spec.DeviceChange[0].Operation = 'edit'
# Required in vSphere 8.0 Update 1 and later
if($global:DefaultVIServer.ExtensionData.Content.About.Version -gt "8.0.0") {
    $spec.VirtualNuma = New-Object VMware.Vim.VirtualMachineVirtualNuma
}
$vm.ExtensionData.ReconfigVM_Task($spec)

We can then verify that limit has been set for the specific virtual disk by now running the following command:

(Get-VM $vmName | Get-HardDisk | where {$_.Name -eq $vmDiskName}).ExtensionData.StorageIOAllocation.Limit