RAMMAP might help. There will always be some fuzz factor in memory reservation.

We have a 512GB RAM host that runs (I know it sounds stupid, but there’s a reason for that) only 1 VM.
The maximum amount of memory Hyper-V allows for this VM is ~490GB. Does it make sense? It doesn’t match the equation above (also saw it on other places).
Do I have a way to troubleshoot it (PerfMon, etc.)?

Thanks.

2008 is not a supported guest operating system for the 2016 release of Hyper-V. I believe the final version that did support it was 2008 R2. I don’t even know what would happen if you tried install the guest services on that OS. I’m assuming that the DOS services wouldn’t work on anything past 2008. So, you’re kind of stuck.
2008 R2 is still supported so you could run that version of Hyper-V.
You’d have a hard time under-sizing a host so badly that it wouldn’t work for this. I have no idea what 8 cores per user does for you. I don’t recall that FoxPro ever used a multi-threaded library and the last DOS version that I saw ran perfectly on a 100MHz single-core CPU with 4MB of RAM. The last Windows version that I saw… I’m fairly certain was about the same. I don’t think that hardware is your concern.

Got a suggestion for the HW requirements and any gotchas and/or recommendations?

I would use teaming, yes. There is not a singular answer to the rest of your question, though. In general, I keep storage communications (iSCSI and SMB) on dedicated adapters but I have no problems with combining all other traffic types.
You might find this article (and maybe even the entire series) to be helpful: https://www.altaro.com/hyper-v/hyper-v-and-networking-part-4/.

If it’s a lab environment, nothing matters unless it’s too overloaded for you to use.

Hi Eric,

Trust you are well. Just want to ask in a lab environment is it ok to Keep Hyper-v host , SCVMM and all the VMs and system files etc. on the same server ? or can you please give me an idea what’s the best thing to do ? I have two HP servers. And what raid you want me to configure ? Please let me know thanks.

You can run as many VMs as you want until you run out of resources.