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Dmitry_Popov's avatar
Dmitry_Popov
Copper Contributor
May 05, 2020

The strange behavior of PowerShell script in disconnected session

Hello! Could you please explain the strange behavior of PowerShell script in disconnected session? During execution of following script PowerShell console hangs after first 32 items been processed ...
Windows PowerShell
Animesh Joshi's avatar
Animesh Joshi
Brass Contributor
May 05, 2020
you're using -inDisconnectedSession parameter which, disconnects the sessions as soon as it starts the command.
Surely you can use invoke-command on more than 32 computers.
Look at example 7 and 18 on https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/invoke-command?view=powershell-7
  • Dmitry_Popov's avatar
    Dmitry_Popov
    Copper Contributor
    May 06, 2020

    Animesh Joshi 

    Example 7 without the inDisconnectedSession parameter.
    Example 18 hangs with busy status if the number of computers is more than 32.
    I found two working crutches for myself, but I would like to understand why it does not work as expected.

    Crutch 1

     

    $computers = (Get-ADComputer -Filter *).name | select -First 35
Invoke-Command -ComputerName $computers -InDisconnectedSession -ThrottleLimit $computers.Count -ScriptBlock {
            $out = $env:COMPUTERNAME
            Start-Sleep -Seconds 10
            return $out
}

     

     Crutch 2

     

    $computers = (Get-ADComputer -Filter *).name | select -First 35
foreach ($item in $computers)
{
	Invoke-Command -ComputerName $item -InDisconnectedSession -ScriptBlock {
            $out = $env:COMPUTERNAME
            Start-Sleep -Seconds 10
            return $out
	}
}

     

    • Mike Shivtorov's avatar
      Mike Shivtorov
      Copper Contributor
      May 08, 2020

      Dmitry_Popov 
      Just use "ThrottleLimit" parameter to specify the maximum number of concurrent connections. Its default value is 32.

      For example, 100 connections at a time:

      Invoke-Command -ComputerName $computers -InDisconnectedSession -ThrottleLimit 100 -ScriptBlock { hostname }

       

      Don't make too many concurrent connections.

      In your latest comment you use "-ThrottleLimit $computers.Count" - it might be too high depending on number of computers in your domain. I guess a hundred or two of concurrent sessions should be more than enough.

       

      Get-Help Invoke-Command -Parameter ThrottleLimit

       

      • Dmitry_Popov's avatar
        Dmitry_Popov
        Copper Contributor
        May 08, 2020

        Mike Shivtorov 

        I understand this, therefore, I asked a question. Earlier, I tried using a parameter ThrottleLimit and concurrent connection. But this led to the hang and the status of the busy.
        for example

        $computer = (Get-ADComputer -filter *).name | select -First 100
Invoke-Command -ComputerName $computer -ThrottleLimit 40 -ScriptBlock {$env:COMPUTERNAME} -InDisconnectedSession

        Now in work I use this option

        $computers = (Get-ADComputer -Filter *).name | select -First 400
$session = foreach ($item in $computers)
{
	Invoke-Command -ComputerName $item -InDisconnectedSession -ScriptBlock {
            $out = $env:COMPUTERNAME
            Start-Sleep -Seconds 10
            return $out
	}
}