Which hypervisor to install on the server?

Question

Virtualization

In the future, the IBM System x3550 M4 server will be released with an Intel Xeon E5-2620 processor (frequency 2.0 GHz and 12 logical cores) and DDR3 memory with a capacity of 64-96 GB (it is not yet known exactly how much will remain). There is support for SAS and SATA drives, storage can always be expanded.
The server is planned to be used for virtual machines (of various kinds - both Windows and Linux, and all sorts of things). Now they are scattered across several Citrix XenServers.
The question is, which hypervisor is the most optimal to put on good, in general, hardware. The main requirements are free and the ability to cope with these resources.
I haven't had any experience with more or less "large" virtualization yet, please share (I run a few pieces on KVM on my working computer).
I'm considering options:

1. KVM - you have to choose something based on Linux (a separate question about choosing a distribution kit), it's not very nice to install an entire OS for the sake of a hypervisor, but it's easy, familiar and convenient.
   
2. FreeNAS - pluses are ZFS, Docker and the ability to combine with a file server (a good opportunity, given the SAS controller), but I have absolutely no idea how it manages virtual machines through bhyve and how to manage them, since I did not work with it.
   
3. VMware vSphere Hypervisor? It's free, but doesn't it have hardware limitations like Citrix XenServer, which only allows one physical CPU in the free version? I couldn't find it in the description, anyway.
   
4. Naked Xen is not a very convenient solution, I'm not eager to mess with it.
   
5. Your suggestions?
   

Thank you.

Answer 1

If already completely free, then Proxmox (KVM + LXC)

Answer 2

Vmware has a free version of vSphere Hypervisor (see Products-Free Products). It does not impose any restrictions on hardware ( https://communities.vmware.com/thread/530333 ). This is if you suddenly want to look towards Vmware)

Answer 3

Isn't it easier to install VMmanager KVM? Price less than 400 rubles. Count free.

Answer 4

The one you're used to working with. Mastering a new hyper is good only when the production does not hang behind your back, when there is time to slowly dissect it. In other cases, focus on familiar tools with which the work will go faster.
JFYI: VmWare has no restrictions - they used to have them, but then they removed them. Its main "limitation" is the impossibility of consolidated management of free versions, vCenter is paid, and only paid hypers can be driven into it. And you can use a stand-alone host for free as much as you like.