Goswin von Brederlow a écrit :
> Gunnar Wolf <firstname.lastname@example.org> writes:
>> Goswin von Brederlow dijo [Tue, Jul 15, 2008 at 11:10:30PM +0200]:
>>>> I don't think that any of the alternatives are valid candidates yet:
>>>> - Linux-Vserver, OpenVZ: clearly not the same use case.
>>>> - Virtualbox, qemu: poor performance under some workloads.
>>> Unusable for production work. Emulation is just too slow. The group of
>>> people that can live with that much slow down compared to xen is
>> Just to state the obvious: I understand your lines applie to
>> virtualbox and qemu, not to linux-vserver, which is completely usable
>> for production work - although it's a completely different approach,
>> completely useless to people who really want seemingly independent
>> full machines (i.e. different OSs or kernel features).
> yes, obviously.
>>>> - KVM: is very promising but is it really a valid alternative *now*
>>>> for current Xen users?
>>> KVM needs hardware support and even then its I/O is slower. It also
>>> deadlocks the I/O under I/O load from time to time.
>>> I could live with the I/O slowdown but nothing will make hardware
>>> magically appear.
>> Please explain further on this. Do you mean that xen can run
>> paravirtualized hosts without the hardware features (i.e. the lesser
>> CPUs sold nowadays) while kvm does require VMX/SVM?
> Yes, xen with paravirtualized hosts runs on cpus without hardware
>> I have not done extensive testing yet (I'm a newbie to both
>> approaches), but I don't feel the slowdown you mention when under kvm.
> The "normal" kvm io uses the qemu device emulation and is dead slow
> and unsecure. As such it is pretty much out of the question for
> production work.
> But kvm can also use the virtio drivers that raise the network speed
> to slightly over 40MB/s. Disk speed is slower but that might just be
> my laptops disk.
With latest kvm version (71), I am able to reach 174 MB/s throughput on
the virtio network interface, so it is now comparable to Xen.
> Now with xen on the other hand I get up to 180MB/s throughput on the
> network interface.
.'`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
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