Secondary VM not booting when cores overlap with primary VM

[mackid1993]

I have a main Windows 11 VM that has a few isolated cores but all cores in my system pinned to it. I also have a secondary Windows 11 VM running the latest 24H2 build for testing. That only has non isolated cores pinned to it. That VM will not boot if my primary VM is running. I'm wondering if two VMs can't share the same cores or of there is a setting I have to change to allow this? The second VM is only used briefly for testing. I'm not worried about performance with it.

 

Thanks.

[mackid1993]

I disabled core isolation and this problem went away. Anyone know why this happens?

[mackid1993]

Thanks to @smdion on Discord. It wasn't core isolation, it turns out I had way too many things pinned to core 0/1 which was causing Unraid to lock up. Unpinning my VMs from core 0 and 1 seems to have stopped everything from locking up.

[mackid1993]

This ended up happening again. It seems to go away when I reboot my server and then after 12+ hours of uptime I can't start a second or 3rd VM.

My primary VM has 32GB of RAM allocated, my server has 64 GB. The other two have 8GB.

 

It's very strange everything is fine up until 12 hours and then the other two VMs won't start. Dialing the RAM on my primary VM back to 16GB resolves everything. Does anyone know why this is?

Edited April 23 by mackid1993

[mackid1993]

Could having XMP enabled be the issue here. I just disabled it, I won't know for 12 hours... but does this sound like XMP being the issue to anyone?

[mackid1993]

Memtest revealed I had bad RAM. Seems like that was the issue. 

Edit: It wasn't! It's a memory fragmentation issue somehow caused by memory backing being enabled on one VM for VirtioFS.

Edited April 27 by mackid1993