KVM steals virtualization spotlight (ZDNet)

Posted Feb 27, 2007 19:04 UTC (Tue) by mikov (guest, #33179)
In reply to: KVM steals virtualization spotlight (ZDNet) by drag
Parent article: KVM steals virtualization spotlight (ZDNet)

Any word on performance of Xen vs KVM ?

KVM steals virtualization spotlight (ZDNet)

Posted Feb 27, 2007 20:34 UTC (Tue) by drag (guest, #31333) [Link] (4 responses)

Xen's paravirtualization is MUCH faster then anything else. Very little overhead.

For Xen total virtualization utilizing VT/SVM vs KVM I don't know, but I expect Xen to be faster.

For Vmware vs Xen/KVM virtualization then Vmware is fastest due to it's highly optimized software emulation. The current generation of hardware assisted virtualization isn't that hot.

I think that KVM still needs work to do for some memory management items and such to get it up to performance, but the Linux kernel guys seem to have done a lot of very nice work with it.

It would be interesting to see some benchmarks on it.

KVM steals virtualization spotlight (ZDNet)

Posted Feb 28, 2007 22:09 UTC (Wed) by mikov (guest, #33179) [Link] (3 responses)

Xen's paravirtualization is MUCH faster then anything else. Very little overhead.

Yes. So, practically speaking, it only makes sense to use KVM if you wanted to run Windows. For Linux guests paravirtualization will always be much faster. Then I don't see what all the excitement really is about.

KVM steals virtualization spotlight (ZDNet)

Posted Mar 1, 2007 3:06 UTC (Thu) by drag (guest, #31333) [Link] (1 responses)

Ever used Xen?
Then you use KVM?

Ever try to use either on your personal desktop?

Then it becomes obvious. :-)

Plus there are a lot of unported OSes out there to play around with or you may need for one reason or another.

Some examples:
Testing installation images for Debian.
ReactOS
OpenBSD
FreeDOS

Here is a example in Debian (for Kqemu)
Install qemu, kqemu-modules-(uname -r) (the experimental branch has the GPL'd version), qemu-launcher.
modprobe kqemu, give yourself permission for /dev/kqemu

Make a directory to house the images.
Copy down the ISO image to that directory or pop in a cdrom.
cd to the directory
run qemu-launcher

select 'use cdrom', leave it at /dev/cdrom or point it at your iso image.
for hda select 'create'.
Make the harddrive image as big as you want. If you choose 'QCOW' format it will only use as much space as is needed for the housed data.

Make sure that 'boot from cdrom' is selected.

Boot and install the operating system.

After install then shutdown. Configure networking, sound, and video card as you please. Boot it up, confirm that it works and then save the configuration.

Very easy.

Btw I found a nice comparison between Kqemu and KVM aviable at:
http://linux.inet.hr/finally-user-friendly-virtualization...

They are both between 80 and 85% efficient at the benchmarks.

KVM steals virtualization spotlight (ZDNet)

Posted Mar 1, 2007 3:21 UTC (Thu) by drag (guest, #31333) [Link]

Oh and btw. The real cool thing about that link is that Kqemu and KVM are pretty much neck and neck when it comes to performance.

I bet with the kernel hackers tweaking everything KVM is faster now by a bit, but that doesn't mean that Kqemu isn't great if you don't have the required cpu extensions.. :-)

KVM steals virtualization spotlight (ZDNet)

Posted Mar 1, 2007 12:20 UTC (Thu) by k8to (guest, #15413) [Link]

> > Xen's paravirtualization is MUCH faster then anything else. Very
> > little overhead.
>
> Yes. So, practically speaking, it only makes sense to use KVM if
> you wanted to run Windows. For Linux guests paravirtualization will
> always be much faster.

Sure, if all you care about is performance.

If being able to conveniently and easily set this stuff up matters to you, KVM begins to look a bit better. Nice management also recommends KVM. Ability to run the latest Linux kernels pushes you towards KVM as well. I would call these practical issues, myself.

Personally I am running FreeBSD and Solaris in minimized windows at the moment (some research of the cousins going on here), and the effort of setting them up and tearing them down is completely trivial. As a (mostly) unpriveledged user I can install these things and launch them with shell aliases. Very, very happy with kvm here.

The video performance with 12 was kind of assy, but it seems decent under 14 now. (I'm relying on Debian packages for my installation, so I'm not on 15 yet. Yes, it was (almost) as easy as apt-get install kvm, try this with xen!)