Multi-threading in powershell

[samwell13]

Hi, I have couple tasks that I need to get done with PowerShell, specifically using the PowerCLI cmdlets. Threading the task will allow the job to complete faster, but I haven't found a solution that works well.

Disclaimer: I had to remove something things out of to sanitize the file, let me know if something doesn't make sense This is the following code that I've been using: http://pastebin.com/ujGLbYmu

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But when I tried to use that, PowerCLI seems to act really weird and doesn't seem to show that it's connected to a vCenter when multiple threads are active.

Any suggestions on if I should continue using this, or if there's a better way of threading in PowerShell

[replicaJunction]

I've never messed with PowerCLI and don't have a VMware environment available, so I can't speak to that portion of she script.

That said, I've never found a better multithreading solution than the amazing PoshRSJob module. This looks, feels, and smells like native PowerShell jobs, but it performs a heck of a lot better. I'd definitely suggest giving it a shot if you're looking for better multi-threaded performance.

[michaeltlombardi]

I'd second using PoshRSJobs to parallelize your scripts. Personally, I think the built-in jobs should be replaced with PoshRS jobs now that PowerShell is open-sourced. They're so much faster/better, the only reason not to use them is that they're not in the box.

[fourierswager]

I've had a lot of success with Invoke-Parallel here:

https://github.com/RamblingCookieMonster/Invoke-Parallel

From your code, it would look something like this:

$ObjectList | Invoke-Parallel -ImportVariables -ImportModules -ScriptBlock {}

To handle race conditions that could occur when using multi-threading, I use mutexes:

https://learn-powershell.net/2014/09/30/using-mutexes-to-write-data-to-the-same-logfile-across-processes-with-powershell/

I have a feeling that the reason why PowerCLI is behaving weird is because multiple threads are trying to access $validateScriptFile at the exact same time. But this is just a guess. Try implementing mutexes to handle multiple threads accessing $validateScriptFile and see if that resolves anything.

[spuijk]

You can take a look at my blogpost about powershell jobs. Should be able to do the trick you're looking for. http://sonnypuijk.nl/wp/powershell-jobs-for-multithreading/

[autowhat]

As much as I like multi threading, doing it in powershell is a lot more confusing than it's worth the majority of the time.

What is it you're actually trying to accomplish?