[CentOS] centos6 xen

Dennis Jacobfeuerborn dennisml at conversis.de
Thu Jul 28 10:54:54 UTC 2011

On 07/28/2011 11:49 AM, Juergen Gotteswinter wrote:
> Am 28.07.11 11:23, schrieb Peter Peltonen:
>> Hi,
>> A few more questions :)
>> On Thu, Jul 28, 2011 at 11:56 AM, John R. Dennison<jrd at gerdesas.com>   wrote:
>>> On Thu, Jul 28, 2011 at 10:53:23AM +0200, Juergen Gotteswinter wrote:
>>>> i think i am not the only one who wants to stay with with xen :)
>>> Far from it.  Xen still has a place as a dom0.
>> What are the reasons for people staying with Xen as dom0, just the
>> learning curve? Or are there some technical considerations as well?
>> Are there any good migration guides from xen to KVM?
>> Can xen domUs be used with KVM easily?
>> I am myself wondering should I learn KVM and go with C6 dom0 or to
>> stick with C5 for now...
>> BR,
>> Peter
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> my experiences with KVM
> - overcomittmend possible ->  very bad in lots of producation systems

How is the *possibility* of overcomittment a bad thing. It gives you 
additional options. In many situation it *is* a good idea and KVM giving 
you the option should be a pro not a con. Nobody forces you to overcommit.

> - vms run as qemu process which take often lots of more memory then
 > assigned to the vm, which could result in swapping (qemu overhead? dunno...)

Define "lots of more memory". Are you sure you are not looking at virtual 
memory and/or buffers?

> - performance Issues, espacially io

Citations needed.

> - cli tools arent as easy to use than xm / xl

If you use libvirt then you can keep using the same tools that you used for 
xen. The fact that the old tools seem to be easier to use i often a result 
of familiarity and not necessarily an indicator that the new tools are 
objectively worse.

I don't have any KVM guest in production yet but I've tested with both 
Linux and Windows 2008 guests and so far I hardly see any difference to my 
Xen guests.


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