[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-users] I want to know if.....
KVM requires virtualization hardware, and the hard-drive is QUEMU, slow, and they don't even have plans to para-virtualize it. I tested the virtio drivers with the current KVM and my virtual machines blew up under pressure. It is not fully-baked yet. But let's define the terms: Windows on Xen requires VTD, or Virtualization-hardware. That is sloooow performance compared with Microsoft Hyper-V R2, maybe a half. SMP is poor, poor. Hyper-V gives a good two way and declines exponentially after that, so the most you can do is two-way. I have over 150 windows 2003 virtual machines in production. On the other hand, Xen domu's is Linux on Linux, and it flies. That is what I call para-virtualization, and I have over 100 of those machines. Vmware, on the other hand, is useless. For example, ESXi does fully-virtualize everything, even Linux domu's, offering maybe 1/2 of the aggregated performance you can get with, for instance, Suse as host and Centos a Domu. Let's be clear, Novell tech support does not "support" Centos or Red Hat as paravirtualized domu's, but it works so much faster that you would be an idiot not to do it, and it is 100% stable I have 100% of my company's business in paravirtualized Domu's under Novell's Suse. There is a powerful reason to prefer Suse as host instead of Red Hat (I have both licenses). If you have a problem, a real problem, Novell actually logs into the server and tries to understand the issue, with a human being. Red Hat is hands-off, I mean, they are not allowed to log into your server. The support is absolutely deficient for a company that cannot go down. So my 5 cents of advice is: Novell as a Host, Centos as Linux Domu or Ubuntu, if you like it (it works), and keep a separate machine for all your windows users. Do not mix them. Federico -----Original Message----- From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Freddie Cash Sent: Thursday, February 26, 2009 6:52 PM To: xen-users@xxxxxxxxxxxxxxxxxxx Subject: Re: [Xen-users] I want to know if..... On February 26, 2009 3:32 pm Venefax wrote: > It is not true at all. KVM and Xen are fundamentally different and > address different problems. Xen allows for fast para-virtualization of > Linux Domus, while KVM only fully-virtualizes. Nobody in his right mind > would use KVM for a linux DOMu, because it would lose 75% of its > performance, compared to para-virtualization. So KVM is for windows on > Xen, but it will never replace Xen in the datacenter. I think you are confusing HVM (hardware-assisted VMs), which both KVM and Xen support, with KVM (kernel-based VM), another virtualisation system. KVM has paravirtualised network, block/storage, and console drivers for Linux and Windows. Same as Xen. There's no "75% loss of performance". -- Freddie fjwcash@xxxxxxxxx _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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