param([int]$YellowTresh = "30", [int]$RedTresh = "50")

# Get root folder object
$entity = (Get-Folder -NoRecursion |Get-View)

# Get disk.maxTotalLatency.latest object id
$maxtotallatencyid = ((Get-View (Get-View ServiceINstance).Content.PerfManager).PerfCounter|?{$_.groupinfo.key -match "disk"}|?{$_.nameinfo.key -match "maxTotalLatency"}|?{$_.RollupType -match "latest"}).key

# get Alarm Manager object
$alarmMgr = Get-View AlarmManager

if (($alarmMgr.GetAlarm($entity.moref)|?{(get-view $_).info.name -match "Host Max Lun Latency"}|Measure-Object).count -eq 0){

	# AlarmSpec
	$alarm = New-Object VMware.Vim.AlarmSpec
	$alarm.Name = "Host Max Lun Latency"
	$alarm.Description = "disk.maxTotalLatency.latest counter alarm"
	$alarm.Enabled = $TRUE

	# Action - Send SNMP Trap
	$alarm.action = New-Object VMware.Vim.GroupAlarmAction

	$trigger = New-Object VMware.Vim.AlarmTriggeringAction
	$trigger.action = New-Object VMware.Vim.SendSNMPAction


	# Transition a - yellow > red
	$transa = New-Object VMware.Vim.AlarmTriggeringActionTransitionSpec
	$transa.StartState = "green"
	$transa.FinalState = "yellow"

	# Transition b - red > yellow
	$transb = New-Object VMware.Vim.AlarmTriggeringActionTransitionSpec
	$transb.StartState = "yellow"
	$transb.FinalState = "red"

	$trigger.TransitionSpecs += $transa
	$trigger.TransitionSpecs += $transb

	$alarm.action.action += $trigger

	# Expression
	$expression = New-Object VMware.Vim.MetricAlarmExpression
	$expression.Metric = New-Object VMware.Vim.PerfMetricId
	$expression.Metric.CounterId = $maxtotallatencyid
	$expression.Metric.Instance = ""
	$expression.Operator = "isAbove"
	$expression.Red = $RedTresh
	$expression.Yellow = $YellowTresh
	$expression.Type = "HostSystem"

	$alarm.expression = New-Object VMware.Vim.OrAlarmExpression
	$alarm.expression.expression += $expression

	$alarm.setting = New-Object VMware.Vim.AlarmSetting
	$alarm.setting.reportingFrequency = 0
	$alarm.setting.toleranceRange = 0

	# Create alarm.
	$alarmMgr.CreateAlarm(($entity).MoRef, $alarm)
	
	if (($alarmMgr.GetAlarm($entity.moref)|?{(get-view $_).info.name -match "Host Max Lun Latency"}|Measure-Object).count -eq 0){Write-Host -ForegroundColor green "done!"}
}
else
{Write-Host -ForegroundColor red "alarm name already exists"}