OT: I still don't get this overblown aversion to virtualizing FreeNAS. People seem to want it - why ignore this user base?
It's not an aversion. Feel free to go and do it. I posted a guide to it somewhere. It is even very well thought out in ways that n00bs tend not to understand.
The problem with virtualizing FreeNAS is that, unlike a typical virtual machine, most people are trying to store huge amounts of data. A virtual environment is already an incredibly complex abstraction, and a ZFS system is also an incredibly complex abstraction. If you are not careful and thoughtful with your strategy, you will end up in an M. C. Escher painting that you may become hopelessly trapped in.
See, for example, I give the very good advice to use actual disks by passing them through to the guest. This gives numerous benefits, including - perhaps most importantly - recoverability during a failure scenario, because you should be able to jettison the hypervisor and boot FreeNAS on the bare metal and recover your system.
The underlying problem is that most people in the N00bs forum experimenting with virtualization will try things that make sense to them because it represents the set of options they have readily available. But making four vmdk files on four drives and using RAIDZ on top of that is going to have inherent risk when one of the disks fails and recovery efforts go sideways. And suddenly it turns out that their only copy of their most valuable data was on those disks because, y'know, FreeNAS protects yer data... right? right???
So here's the deal. If you can go and read my "how to virtualize" post and you understand everything in it, then I will declare you competent to virtualize FreeNAS, and will even provide a money-back guarantee... should virtualization fail you, I will return every last penny you paid for my virtualization guide. No refunds for lost bits though.
But until you've sat around here for a few years, watching the failures and tears of users who thought they knew what they were doing and instead lost their data, please don't talk to me about "ignoring this user base." I got frustrated and wrote the guidance both for n00bs not to virtualize, and also the guidance that gives experts a well-thought-out, workable recipe. No part of the user base has been ignored. There is no magic wand that can make the n00bs suddenly make better choices and understand all the complexity sufficiently to allow them to be successful.