How to Increase number of cuncurrent powershell instance on VM?

Given the following sample script:

Workflow Test-Workflow{    foreach -Parallel -ThrottleLimit 10 ( $Number in 1..20 )    {        $RandomSeconds = Get-Random -Minimum 10 -Maximum 60        InlineScript        {            $String = '{0:s}: Starting number {1:D2} for {2:D2} seconds' -f (Get-Date),$Using:Number,$Using:RandomSeconds            Write-Host -Object $String        }        Start-Sleep -Seconds $RandomSeconds        InlineScript        {            $String = '{0:s}: Stopping number {1:D2} after {2:D2} seconds' -f (Get-Date),$Using:Number,$Using:RandomSeconds            Write-Host -Object $String        }    }}Test-Workflow

You will get output similar to the following:

2017-11-28T13:27:34: Starting number 09 for 25 seconds2017-11-28T13:27:34: Starting number 10 for 36 seconds2017-11-28T13:27:34: Starting number 08 for 53 seconds2017-11-28T13:27:35: Starting number 06 for 17 seconds2017-11-28T13:27:35: Starting number 07 for 28 seconds2017-11-28T13:27:35: Starting number 05 for 33 seconds2017-11-28T13:27:35: Starting number 04 for 49 seconds2017-11-28T13:27:35: Starting number 02 for 18 seconds2017-11-28T13:27:35: Starting number 03 for 47 seconds2017-11-28T13:27:35: Starting number 01 for 45 seconds2017-11-28T13:27:52: Stopping number 06 after 17 seconds2017-11-28T13:27:55: Starting number 11 for 49 seconds2017-11-28T13:27:55: Stopping number 02 after 18 seconds2017-11-28T13:27:55: Starting number 12 for 55 seconds2017-11-28T13:28:00: Stopping number 09 after 25 seconds2017-11-28T13:28:00: Starting number 13 for 37 seconds2017-11-28T13:28:03: Stopping number 07 after 28 seconds2017-11-28T13:28:03: Starting number 14 for 46 seconds2017-11-28T13:28:08: Stopping number 05 after 33 seconds2017-11-28T13:28:08: Starting number 15 for 48 seconds2017-11-28T13:28:11: Stopping number 10 after 36 seconds2017-11-28T13:28:11: Starting number 16 for 57 seconds2017-11-28T13:28:21: Stopping number 01 after 45 seconds2017-11-28T13:28:21: Starting number 17 for 22 seconds2017-11-28T13:28:22: Stopping number 03 after 47 seconds2017-11-28T13:28:22: Starting number 18 for 39 seconds2017-11-28T13:28:24: Stopping number 04 after 49 seconds2017-11-28T13:28:24: Starting number 19 for 34 seconds2017-11-28T13:28:28: Stopping number 08 after 53 seconds2017-11-28T13:28:28: Starting number 20 for 58 seconds2017-11-28T13:28:37: Stopping number 13 after 37 seconds2017-11-28T13:28:43: Stopping number 17 after 22 seconds2017-11-28T13:28:44: Stopping number 11 after 49 seconds2017-11-28T13:28:49: Stopping number 14 after 46 seconds2017-11-28T13:28:50: Stopping number 12 after 55 seconds2017-11-28T13:28:56: Stopping number 15 after 48 seconds2017-11-28T13:28:58: Stopping number 19 after 34 seconds2017-11-28T13:29:01: Stopping number 18 after 39 seconds2017-11-28T13:29:08: Stopping number 16 after 57 seconds2017-11-28T13:29:26: Stopping number 20 after 58 seconds

As you can see from the Output, 10 instances of the loop are running concurrently even though I do not have 10 powershell.exe instances running. You can use InlineScript like in my example above to visually see when your workflow is starting and/or stopping an instance of your loop.

If I understand your question correctly, yes, there seems to be a difference between launching powershell processes and running builtin powershell (emulated) commands in a workflow. It seems to limit the process count to 5 in task manager. Maybe you can update your example with what you are running. Maybe you'd prefer jobs or start-process.

 workflow work { foreach -parallel ($i in 1..10) { powershell "sleep 10; echo done $i" }  } measure-command { work } | fl seconds Seconds           : 35 workflow work { foreach -parallel ($i in 1..10) { sleep 10; echo done $i }  } measure-command { work } | fl seconds Seconds           : 14

EDIT:

Uhh, it can be done. It's somewhat involved. You have to be administrator, and psremoting has to be enabled. Although I saw more processes run, it actually took longer to finish.

# all default to 5$wfopt = New-PSWorkflowExecutionOption -MaxSessionsPerWorkflow 20 -MaxSessionsPerRemoteNode 20 -MaxActivityProcesses 20Register-PSSessionConfiguration -Name myworkflow -SessionTypeOption $wfopt -SessionType Workflow -Forcework -PSConfigurationName myworkflow

You can use Set-PSSessionConfiguration to modify it, Get-PSSessionConfiguration to check it, and UnRegister-PSSessionConfiguration to remove it.

You could modify the default config too, Microsoft.PowerShell.Workflow, but the changes are permanent.

I using PS v5.1 and still have the same limitation.Is there a way around these limits on some newer version of PS? Maybe on PS6?

Name                           Value----                           -----PSVersion                      5.1.17134.858PSEdition                      DesktopPSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}BuildVersion                   10.0.17134.858CLRVersion                     4.0.30319.42000WSManStackVersion              3.0PSRemotingProtocolVersion      2.3SerializationVersion           1.1.0.1

Follow the code and results:

foreach -parallel -throttlelimit 10 ($i in 0..20){    "start #$i"    InlineScript { "    inline #$using:i" }}start #9start #8start #7start #6start #5start #4start #3start #2start #1start #0    inline #    inline #    inline #    inline #    inline #start #10start #11start #12start #13start #14    inline #    inline #    inline #    inline #    inline #start #15start #16start #17start #18start #19    inline #    inline #    inline #start #20    inline #    inline #    inline #    inline #    inline #    inline #    inline #    inline #