I have a single 2016 Hyper-V server with 2 CPU (16 cores) and 128GB RAM.
The server hosts 6 VMs all with static memory allocations.
- VM1 - 4GB + 2 vCPU
- VM2 - 4GB + 2 vCPU
- VM3 - 24GB + 4 vCPU
- VM4 - 48GB + 8 vCPU
- VM5 - 1GB + 1 vCPU
- VM6 - 8GB + 2 vCPU
In total, I have allocated 89GB to VMs, leaving approx 30GB spare (less Hyper-V usage)
VM4 is reporting high memory demands and I have tried to increase it to 60GB (+12GB) buy Hyper-V advised I have insufficient memory when I tried to start the VM.
p.s. I disabled NUMA as this "appeared" to be causing performance issues. Before disabling VM4 had 60GB and displayed "Memory Spanning". I have read articles that both advise to enable & disable NUMA.
What is going on here?