Windows Server 2019 Guest RAM assingment

[SkywalkerIsNull]

Hello Everyone,

This one has been troubling me for a while, and I cannot figure out what is going on. We have a windows Server running Hyper-V that has 2 VMs, one is a Linux (that does not seem to have any issues) and the other is a Windows Server 2019.

Both VM's are provisioned with 200GB of RAM at startup (whole system has 768GB RAM) so start up is fine, and they can dynamically increase the amount of RAM. But at some point, the windows guest starts to decrease the amount of RAM that is available to a level that is below the minimum, see the screen shots below:

Task Manager Guest VM:

Note that it shows 72GB of RAM available.

Host OS Hyper-V:

Host OS Task Manager:

Guest OS RAM config:

What can I look into to try and troubleshoot this?

[#2]

Something here could help.  

Hyper-V Dynamic Memory Overview | Microsoft Learn  

[#3]

Hey Dave,

Looking through that link, there is not anything that is standing out or useful. This particular setup has been fine for nearly 3 years without any issues. It seems that only in the last month (that I have noticed it as the users don't always see these sorts of details) that this issue has appeared. There have been no updates or changes to the Hyper-V settings for more than 6 months.