During Discovery, MID Server hosts use an unexpectedly large amount of Memory running multiple powershell.exe processes, in addition to the JVM memory - Known Error

During Discovery, MID Server hosts use an unexpectedly large amount of Memory running multiple powershell.exe processes, in addition to the JVM memory Description MID Server hosts use a surprising amount of Memory running multiple powershell.exe processes, in addition to the JVM memory.

A basic 25 thread MID Server is likely to run 25 powershell threads in parallel regularly, and without doing anything particularly taxing in the Powershell script can end up using an additional 2GB of server memory simply for the powershell.exe processes.

A MID Server with increased thread count will have a proportionally worse Powershell memory footprint.

The memory used by powershell ends up overshadowing that used by the MID Server application JVM. This memory usage is not very well understood, or documented in the

Steps to Reproduce

- Configure a MID Server host with the recommended 5GB of RAM (4GB for OS, 1GB for JVM) for a Service Mapping + Discovery + Orchestration implementation. (https://docs.servicenow.com/csh?topicname=r_MIDServerSystemRequirements.html&version=latest) - Discover a network containing a large proportion of Windows servers. - Observe Windows Task Manager / TASKLIST and keep an eye on the memory usage by the multiple powershell.exe threads. Thread dumps of the MID Server applicaiton at the time shows what probes/patterns are running.

Fom the command line (as administrator), running... tasklist | find "powershell" ...will output something like this. powershell.exe 31044 Services 0 85,708 K Unknown NT AUTHORITY\SYSTEM 0:00:01 N/A powershell.exe 37528 Services 0 77,440 K Unknown NT AUTHORITY\SYSTEM 0:00:01 N/A powershell.exe 34924 Services 0 80,712 K Unknown NT AUTHORITY\SYSTEM 0:00:01 N/A powershell.exe 38644 Services 0 76,896 K Unknown NT AUTHORITY\SYSTEM 0:00:01 N/A powershell.exe 38272 Services 0 85,880 K Unknown NT AUTHORITY\SYSTEM 0:00:01 N/A powershell.exe 9424 Services 0 22,020 K Unknown NT AUTHORITY\SYSTEM 0:00:00 N/A powershell.exe 38188 Services 0 16,476 K Unknown NT AUTHORITY\SYSTEM 0:00:00 N/A powershell.exe 33376 Services 0 80 K Unknown NT AUTHORITY\SYSTEM 0:00:00 N/A powershell.exe 22740 Services 0 80 K Unknown NT AUTHORITY\SYSTEM 0:00:00 N/A

That's simply from a windows 10 laptop discovering another windows laptop multiple times at once that doesn't even have credentials set up, so this represents a few Windows - Classify probes running and failing on credentials. 25 threads at 86MB each is potentially an additional 2GB of memory.

Other customer examples have included a 8GB windows host dedicated to a single 200 Thread MID Server, with powershell.exe threads using up to 90MB each and having over 60 powershell.exe threads running at once. This crashes the MID Server when the OS is unable to provide the JVM with any more memory when it requests it.

Workaround This problem has been fixed. If you are able to upgrade, review the Fixed In section to determine the latest version with a permanent fix your instance can be upgraded to.