Should I be using xen?

I’ve been using Virtualbox for a couple of years now to run a work provided Windows XP image under linux. I have the set-up on a couple of PC’s, on the one at home at runs fine, on the one at work (less powerful) it is a bit clunky at times. On top of that, I have to say I am not keen on Oracle as a company and am very unconvinced about their commitment to open source.

Virtualbox is easy, works OK, supports USB pretty well (necessary), but I was wondering if I should move to a hypervisor (ie xen).

So, I am under the impression that as the OS is closer to the metal with xen that the OS would run better, is that true? That some hardware that Virtualbox struggles with might work better (for the same reason), true?

Can I even run Win XP and openSUSE together under xen? If I do, can I switch between the two on a desktop PC simply (with both running obviously), sharing keyboard, mouse etc?

Will the set-up be too complicated (I’ve been using linux for about 15 years, but am not a software engineer, nor a virtualisation expert)?

Any other comments? (You can tell I know nothing about xen can’t you…?)

Using Xen… well, it depends.

If you need highest possible performance and efficiency and you are running server type workload in VM then yes, it could be better. The reason is that Xen support paravirtualization (PV) - there is a special kernel-xen which can communicate directly with the host system (hypervisor) and skip some overhead related to virtual HW emulation. E.g. in Xen there is a virtual network device which doesn’t emulate any PCI network card but directly asks the host system to send the packets. Similar with disk devices. So network or disk intensive workloads will be faster and need less CPU in Xen paravirtualized machine, as the unnecessary DMA and IRQ simulations are skiped.

Xen also supports full virtualization (FV) - this is similar to KVM/VirtualBox/Qemu… it emulates some PCI devices for network and disk access. This type is required for MS Windows as there is no Windows kernel for Xen.

It should be quite easy to configure Xen machine - there is a Yast tool to install all needed Xen packages. The management can be done also from GUI with virt-manager.

On the other hand if you need easy to use virtualization tool and don’t care about slightly less performance then I’d suggest to stay with VirtualBox. I very like the ease of creating virtual machine snapshots (with single click) and easy moving between them. I use VirtualBox for testing YaST in different environments (openSUSE, SLES, different service packs) and I need very easy way of rolling back when I break something or when I need to do the test again.

Of course, with Xen it is also possible to create snapshots, but it’s not that easy. (Maybe it has changed, I haven’t used Xen several years - since I moved to VBox).

You can run both Windows and Linux in Xen virtual machines, sharing keyboard and mouse works the same way as in any other virtualization system - the focused virtual machine receives the mouse clicks and keyboard presses.


I hear Red Hat is putting their weight behind KVM, which they moved to from Xen.

From my experience the functionality of Xen on openSUSE is very limited (tried it on 11.3). The functionality of virt-manager is very limited and I was not able to find xe cli package (I’m talking about Chapter 5. Command line interface). The xe cli is very nice and allows for making snapshots and everything else You need but gets a bit of time to get accustomed to.

The other problem with Xen is that You have to boot your desktop from a xen kernel as well. I haven’t tried KVM but it seems a more reasonable choice. Other than that sticking with Virtualbox is not a bad idea especially if You already know it.

From my experience Xen is only usable on Citrix XenServer, which is a hypervisor that resembles RedHat in some way, free to use with the free license but I don’t think it’s a good choice for a desktop.

Best regards,

dragonbite wrote:

> I hear Red Hat is putting their weight behind KVM, which they moved to
> from Xen.
Similar situation for SUSE and hence for openSUSE. There is not even a
manual for Xen shipped these days (it was in older versions) only for KVM

PC: oS 11.4 64 bit | Intel Core i7-2600@3.40GHz | KDE 4.6.0 | GeForce GT 420
| 16GB Ram
Eee PC 1201n: oS 12.1 RC2 64 bit | Intel Atom 330@1.60GHz | KDE 4.7.2 |
nVidia ION | 3GB Ram

Thanks for the responses, appreciated. So I guess I should be substituting KVM for xen in my question, but the same questions apply. However, looking at the answers I guess It’s probably easier to stay with the set-up I have?

Have a look here: [Phoronix] Ubuntu 11.10: Xen vs. KVM vs. VirtualBox]( Kvm and virtualbox are almost neck & neck. I would have expected virtualbox to blow everything else out of the water. If kvm gets 3D support, it will be hard to decide between it and VB.

If you don’t mind the closed source, IME for non-server full virtualization vmware player performs better than virtualbox. At least that was my impression the last couple times I compared both running a windows XP VM. I wanted to use VB due to it’s open source stance, but ended up using vmplayer both times.

Thanks for the link. I think I’ll check out KVW against vmplayer.

Kvm is nice, but nothing I’ve used compares to the user friendliness/ ease of use of vmware. If all you need is simple virtualization, the free vmware player is nice also. It is on par with virtualbox.

Interesting. My employer actually provided me with a vmware image and suggested using vmplayer to start with and I found the performance (on my limited work PC) to be dreadful. They have a huge amount of monitoring going on in their windows set-ups (every process run is logged for a start) and it slows things to a crawl at the best of times, but when I converted the image to VBox it ran much better. Perhaps VBox performs better on limited hardware?

I wouldn’t think so. Perhaps you didn’t have wmware-tools installed in the image?

I did have vmware tools installed. I did do wonder whether player was crippled to some extent compared with workstation. On the other hand, our work image has a crazy number of scripts running, it could just be that one of those was hitting something vmware player didn’t do well, but VBox did. Dunno.