# Which VM should I choose (KVM,QEMU,VirtualBox,Xen)

## Saundersx

Right now I run VMWare because, for no other reason, I'm lazy and it just "works". I have been reading into VMs that are closer to the metal and supposedly they give better performance and gobble less resources. I have an AMD 8350 CPU and a GA-990FXA-UD3 MB which supports IOMMU so I should be good to go (or so I have read).

The video card is a Nvidia 660Ti 2G. My only real requirement for switching is PCI Passthru without buying a second dedicated GPU. I read it can be done but not necessarily with my card.

So my question is which, if any, VM can do what I want? I will probably be running WinXP/7 or whatever MS garbage works the best on it.

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## Anon-E-moose

I have a few qemu/kvm vm's, running XP and Win7. Hardware is listed in my sig. 

I have an nvidia 210 that I use for X and the some of the XP vm's. 

I do have a second card a radeon that I pass through to some of the vm's, I don't use it at all in linux.

I only use it for one vm and that's for game playing.

Radeons are easier to pass through than nvidia, from what I've seen, at least from the multi card aspect.

I also have a pcie network card that I pass through to the vm's so I wouldn't have to deal with bridging, etc.

I have had to use the "iommu=pt" flag on the grub cmdline for it to work properly (amd's typically need this)

I've never run xen and it's been a long time since I ran virtualbox. So I can't really give a comparision.

Good luck

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## 666threesixes666

if you're wifi only do virtualbox, if you're on a wired server, kvm and document the tap tun stuff.

if you're looking to make a turnkey vm to share online virtualbox.

depends on the situation.

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## Saundersx

 *Anon-E-moose wrote:*   

> 
> 
> I have an nvidia 210 that I use for X and the some of the XP vm's. 
> 
> 

 

Are the VMs running in a window or do you give them passthrough?

 *Anon-E-moose wrote:*   

> 
> 
> I have had to use the "iommu=pt" flag on the grub cmdline for it to work properly (amd's typically need this)
> 
> 

 

same here...

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## vaxbrat

Last time I used xen was over five years ago on an rhel5 installation to paravirtualize a windows guest.  Also around the same time I used Vmware "system" when it was available for free on gentoo in a couple of places.  The web interface for v2 left a bad taste in my mouth so I looked at qemu and then kvm and haven't looked back since.  That being said, work is a bit winders centric so I still deal with vmware workstation installs and a couple of ESX with VSPHERE on a regular basis.  While I don't have benchmarks to back my claims, I find the Win7 guests with virtio driver support regularly smoke the vmware workstation (on Win7 hypervisor) network drivers in performance.  The RedHat qxl gpu driver and the virtio disk drivers appear to me to be more of a wash compared with their vmware counterparts.  The virtio net does need a bit more care and feeding if you do weird things with the bridge such as having a requirement to do multicast routing.

I use the virt-manager and spice support for the guest management so the console will be in a window.  I have my corporate desktop set up this way and have a smart card reader on the usb passed up to the Win7 guest to do my two factor stuff in Winders.  I also like to run the guest vm files on btrfs so I can snapshot and quickly roll back vm state if necessary.

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## Saundersx

After much reading it appears if you want vga passthrough on your primary card you have to start it from console. The performance looks to be almost on par with native but booting into linux console (as opposed to simply starting it within a dm like kde) defeats the point a bit.

The only current way is to buy a second card, which in turn means running it off a second monitor. Also "sharing" the keyboard/mouse seems a pita as well. Unfortunately I'm not interested in this way either.

If I am wrong on any of this please correct me.

most of my info came from

http://wiki.xen.org/wiki/XenVGAPassthrough

https://bbs.archlinux.org/viewtopic.php?id=162768

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## Anon-E-moose

In  my case, I have a viewsonic monitor with two hdmi inputs as well as a vga, 

so when I start my vm that uses the second card I simply switch inputs to my monitor.

It all depends on what kind of interfaces your monitor has.

I use my normal keyboard/mouse for vm usage, but I do have the ability to use

a secondary set as I pass through some of the usb ports on my MB.

As far as buying a second card it depends on what you are planning to use the vm for.

As I stated I have a few XP vm's that simply use the main video card (nvidia).

I keep the second one for gaming usage, as it provides better performance in that instance.

Xen is a whole different beast than just running a qemu/kvm session under linux.

It all depends on what you want.

Give us a real life scenario of what you intend to do and you will get better answers.

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## Saundersx

Well hardware acceleration for stuff like Photoshop/Premiere (using PS is part of my job so don't get all Stallman on me  :Very Happy:  ) and some gaming. Like I said VMWare just "works" and works quite well but it is a little sluggish for what I use it for however gaming is out of the question. Also a speed boost is always welcome.

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