Real time disk IOPS and latency monitoring using PowerShell

The below code collects disk IOPS and average IO latency of a list of servers and output the real time values.

Note: Here we are monitoring only logical disk E of testvm-01, testvm-02 and testvm-03

while($true)
{

$Servers = "testvm-01","testvm-02","testvm-03"

$R_io = '\LogicalDisk(E:)\Disk Reads/sec'
$W_io = '\LogicalDisk(E:)\Disk Writes/sec'
$Lat = '\LogicalDisk(E:)\Avg. Disk sec/Transfer'

$Reads =  (Get-Counter -Counter $R_io -ComputerName $Servers).CounterSamples.CookedValue
$Writes = (Get-Counter -Counter $W_io -ComputerName $Servers).CounterSamples.CookedValue
$Latency = (Get-Counter -Counter $Lat -ComputerName $Servers).CounterSamples.CookedValue

clear

"{0,-15} {1,-15} {2,-15} {3,-15} {4, -15}" -f "Host", "Reads/Sec", "Writes/Sec", "Total IOPS", "Avg Latency (ms)"

echo `n

for($i=0; $i -le 2; $i+=1){

[int]$R = $Reads[$i]
[int]$W = $Writes[$i]
[int]$T = $R+$W
[int]$L = ($Latency[$i])*1000
[String]$N = $Servers[$i]

"{0,-15} {1,-15} {2,-15} {3,-15} {4,-15}" -f "$N", "$R", "$W", "$T", "$L"

}

}

Running a PowerShell script on multiple remote machines simultaneously

Below example shows how to trigger PowerShell scripts on a remote Windows machine and run as background jobs.

trigger.ps1

Invoke-Command -ComputerName testvm-03 -ScriptBlock {&C:\posh\io\iostress.ps1} -AsJob
Invoke-Command -ComputerName testvm-02 -ScriptBlock {&C:\posh\io\iostress.ps1} -AsJob
Invoke-Command -ComputerName testvm-01 -ScriptBlock {&C:\posh\io\iostress.ps1} -AsJob

Invoke-Command is used to execute scripts remotely. Above script (trigger.ps1) invokes a PS script (iostress.ps1) on 3 remote machines. Here the script being executed is saved on the corresponding remote machine itself. As each of the invoke-command is running as a background job on the local machine, the second invoke-command doesn't have to wait for the first invoke-command to complete and the third invoke-command doesn't have to wait for the first and second invoke-commands to complete. From the user perspective the command prompt returns immediately even if the jobs take longer time to complete. This case will be useful if you want to run a script on multiple remote machines at the same time.