[CentOS] upgrading Centos-Xen when version 6 comes along
heinlein at madboa.com
Wed Nov 17 16:38:43 UTC 2010
On Wed, 17 Nov 2010, Rudi Ahlers wrote:
> Have anyone used both XEN & KVM before? What are your experiences
> with either, in comparison to each other? We've been using XEN for
> about 4 years now, and only use CentOS as our server platform. I'd
> hate to move to Debian or OpenSuse just for XEN, and I don't know
> KVM at all.
We run both Xen and KVM under CentOS 5 (on separate machines, of
course) and I haven't been able to spot significant performance
differences between the two.
RHEL 6 is supposed to contain a Xen-to-KVM migration tool, but I
haven't seen it in action.
It took me a while to figure out the KVM/libvirt XML configuration
files; some cookbook-style documentation for them would be a great
The biggest single up-front difference for me on CentOS machines was
that KVM hosts default to NAT on a private bridge while Xen hosts
default to straight bridging. Some network tweaks are necessary to get
KVM hosts to live on a straight bridge.
Also, if you assign MACs to your VMs at installation time (I do, for
DHCP- and DNS-related reasons), you should note that KVM MACs lives in
a different namespace: 54:52:00:xx:xx:xx.
I haven't done host migration with Xen, but it works quite well with
KVM -- once you have the shared storage and security mechanisms
Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/
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