>coming from your link in chatter
>
>>https://voat.co/v/technology/comments/835741
>
>Googling Microsoft Hyper-V Server license terms also have some weasel parts in them - better compared to the things I remember from Win X, but they link to documentation for server 2008(??), where "in some cases" a hardware ID will be included. Combined with the right to change services customer has no standing IMO with lawyers available to him...
>
>Reading comparizons of other hypervisors I reached following temp map:
>
>Hyper-V

• + best perf for all Windows guests with paravirtualization across versions, Linux support good enough (fits my profile...)
• + broad HW support
• - closed source
• - phones home (?)

- Performance (not talking about PV for the moment): my understanding is there's very little difference between any of the major hypervisors. Years ago there was a lot of difference, but modern hardware has Intel VT-x with Extended Page Tables (or the AMD equivalent) and AFAIK all major hypervisors make use of that.

- PV: can help a lot, if performance is a big issue you'll need a platform that supports it in your guests. Hyper-V has PV support for some Linux guests; some distros have guest additions built-in (e.g. Ubuntu)

- Phoning home: Hyper-V is designed to scale up to data center/cloud levels. Those operators do not appreciate software phoning home and have the skills to prevent that. Even if MS's EULAs allow Hyper-V to phone home I'd be surprised if it does in practice

- Backup: if guests support VSS there are some interesting guest backup options such as Altaro. Apparently VSS support for some Linux guests (again Ubuntu as an example) is available. This enables backup of running VMs without suspending them, which is cool. Altaro also does smart reverse-differential backups using VSS so backups are typically small and quick (reverse incremental means it's quick to restore the most recent backup, unlike with regular incremental where you need to restore all the incremental backups to get to the most recent state). I have one client with 5 Ubuntu guests on Hyper-V and backup with Altaro isn't quite working as I'd like it yet, still have some work to do there.

>Citrix XenServer

• + total stack OS, including managment tools
• + managment up to enterprize level, but only text based
• o Paravirtualization only since 2015, unclear for which windows versions
• - HW support lagging behind Hyper-V and VMWare
• - Windows guest support last to implement "new" features when compared across hypervisors, often playing catchup?
• - not even Web managment GUI ?

- My understanding is Amazon is the only major operator running XenServer, and the only reason someone setting up new virtualization infrastructure would choose it would be if they are contemplating moving a small on-premise environment to Amazon at a future date.

- A client loaned me a small server last year and asked me to look into setting it up with XenServer. I didn't take many notes at the time but as I recall it installed easily and I set up a couple of Ubuntu Server guests with no issues.

- You get a basic management interface on the host console but you don't get GUI views of the guests (like you do with Hyper-V). I ended up setting up an X Window client on my Win7 box from which I could get sessions on the Ubuntu guests which was a chore to set up and klunky to use in practice. I think it's much easier to manage things from Linux boxen. My understanding is (at that time) there were a few projects working on native Windows management tools but I did not find any free ones that were complete and/or production-ready

- My understanding is Citrix has given up fighting VMWare and Microsoft and they're really only in the space to support existing customers. But considering the size of Amazon that's not a small thing

>VmWare vSphere/ESXi

• + small footprint
• + dynamic physical memory allocation between guest VM's with very little overhead
• + Windows and Linux guest support well/best balanced
• - paravirtualized disc access only for new windows versions (>= Vista, XP worker VMs therefore slower? Unclear if/which driver is supported in XP in latest version [boot and/or data discs] and how it compares in speed to newer OS versions)
• - free managment utilities do not support newest and best options (virtual HW support?)
• (- VMs are not allowed very beefy CPU configs typical for server VMs, no problem for me, 1 - 2 cores typical for me)

I haven't used it. My understanding is VirtZilla is usually the first to offer advanced features and has a lot of mind share in the largest environments. Not sure those features are of much use in smaller environments. I get the feeling if you want to get the absolute most efficient use of hardware then VMWare is the way to go, it offers the most advanced memory and CPU management i.e. you can effectively run more VMs on the same hardware with VMWare.

I also understand VMWare products have by far the largest and most comprehensive ecosystem for management etc. But all of the products are neither free (as in libre) nor cheap.

>RHEL KVM

• + fully OS
• + paravirtualized disc access up to XP (good in my case, as I want high perf WS not talking home)
• + good support for newer Windows OS (dev/test tasks)
• - Linux guests are best supported if compared across guests in KVM (which I need mostly for surfing only)
• - Windows guests need quite bit of txt-based config?
• - needs more Linux knowledge than currently available near this KB

KVM is available on any modern Linux distro, it's not Red Hat specific (I'm sure you knew that but lurkers might not). My understanding is it's the go-to choice if you don't want either VMWare or Microsoft. It seems to have taken the baton from Citrix/XenServer. I don't know about the management ecosystem but my understanding is there's been a ton of activity in the last couple of years (unlike Citrix/Xen) so I'd think there should be some good options out there.

The above are products mostly aimed at installation on dedicated server computers (possible exception being KVM on Linux). If anyone is interested in running VMs on a Windows workstation, Oracle VM VirtualBox is a reasonable free choice. There apparently is a version of VirtualBox for Linux but a few years back it was buggy and I don't know of any reason you'd want to use that instead of KVM on a Linux workstation.

VMWare offers a Workstation product for desktop virtualization. I understand it's the gold standard but it's not free or cheap.