There is still no guarantee that even modified drivers will work, however, due to the way NVIDIA drivers function. There are a lot of people, who have spent a lot of time, to get it to work - with some success; but, everything I've read points to this being something you'll have to screw around with and "maintain" regularly to keep it working. If you're expecting it to be a smooth, easy, and "permanent" process, I would recommend not even starting to try it on Xen (Server or XCP-NG).

If you REALLY need to do this with VMs, KVM and unRAID both have built-in capabilities to do this - which seem to work a bit better than others. vmWare is supposed to have a similar feature; but, I've not gotten it to work. I will tell you, that in messing around with this on all the hypervisors, even on KVM and unRAID, some card\driver combinations just will not work, and, you'll honestly waste more time screwing around with it than just spinning up a dedicated box or grabbing an AMD card. I'm not an AMD guy, and I didn't choose that route myself; but, they at least do not have this "limitation" in their driver stack.

Don't think NVIDIA will come around and fix it, either - their forums are rife with this topic; and, they've pretty much said "we don't have any plans to fix this bug [that we actually introduced on purpose]".

@fohdeesha I'm going to be honest with you. I've had terrible luck with FreeNAS more times than I can count. It's always been a mix of hardware compatibility issues, appearance of reliability, a not-so-great interface, and a slew of others. I've found unRAID to suffer from similar things. I know a lot of people who use it; and, online, it's obviously widely used by a very large audience - it just doesn't seem to work well for me. I just recently spent at least a couple days trying to use it in front of a fiber-channel array to no avail.

I am about to drain and rebuild an x86-based storage appliance (currently running XPenology) in the next few weeks, so, I may go ahead and try it on this piece of hardware and see where it gets me. I loved OpenFiler back in the day, and, had pretty good luck with Nexenta for a while; but, one is just asking to be compromised using it in 2020, and the other doesn't scale well with modern storage without spending a fortune. XPenology works great, and gets you all the ease of Synology; but, it is very finicky about hardware. I ultimately had to settle with a solution that I really don't like; but, it works for now (Windows Server on vmWare, with the FC array passed through as a RAW disk).

@beagle The simple answer here, which has been implied by others, is...

You DO NOT, EVER, install other "services" on your hypervisor in a production environment - no matter what your cost, convenience, etc. "desires" are.

That's just not how this is all supposed to work; and, any technical guy worth his job position will know right away to not only recommend against setting it up like that, but, will adamantly decline being "forced" to do so - consequences be damned.

What is even worse, is you mentioned a 20 TB requirement for file server storage. There is literally only one solution for this...

A DEDICATED file server - whether that be a VM with enough attached storage (VDIs using workarounds, iSCSI\NFS\SMB direct attached), or you build a back-end NAS system that either passes off the data directly, or utilizes a front-end file server "proxy".

You also claim a need for high-performance - this automatically dismisses any "cheap" solution that aligns with some of your concepts above. Do it right...the first time.

There is a huge difference between "finding a creative solution" and "ignorantly (intentionally or not) pursuing an unrealistic and ill-advised idea".