Four-node Windows Server 2019 Hyper-V cluster, balancing 80 VMs. Cluster was created over 6 months ago, is stable, and migrates/balances VMs successfully.
Three identical VMs running Windows Server 2008 R2 were changed to increase processors and memory from 8/16GB to 16/32GB on 9 January. It was discovered today that the guest OS only sees 8 processors instead of the configured 16. No other changes were made, and we have other similar VMs that run 16/32GB without issues.
Using PowerShell we're unable to find any differences in the VM configuration between VMs seeing all 16 processors vs. the three VMs that don't. Reducing/increasing processors and memory on the three VMs makes no difference. Allocated memory is recognized as set, but no more than 8 processors are recognized by the guest OS.
We've confirmed we can create a new VM and attache the existing virtual disk to side-step the issue, but this is cumbersome due to extensive network configurations that then need to be recreated from scratch.
Does anyone have any insights are what/where we might find the cause or resolution?