Re: Limited IOP/s on Dual Xeon KVM Host

[Stefan Priebe <s.priebe-2Lf/h1ldwEHR5kwTpVNS9A@public.gmane.org>]

Am 10.11.2012 14:41, schrieb Mark Nelson:
> On 11/10/2012 02:03 AM, Stefan Priebe wrote:
>> Hello lists,
>>
>> on a dual Xeon KVM Host i get max 6000 IOP/s random 4k writes AND reads.
>> On a Single Xeon KVM Host i get 17.000-18.000 IOP/s write and read. I
>> already tried to pin the kvm process using numactl and also the fio
>> process but it doesn't help on the dual xeon.
>>
>> 10GBE Network is fine. I get 9.8Gbit/s on both hosts. Kernel is also he
>> same on both.
>>
>> Anybody an idea?
>
> When you say KVM host, do you mean the underlying node or the virtual
> machine instance?
Sorry i'm talking about the vm host regarding the HW. The vm instance is 
always the same.

> If you mean underlying node, it could be remote memory access or if you
> are on a last gen xeon if you have dual io hubs, you could be hitting a
> remote io hub for the network card.  I wouldn't think that would cause
> such a big hit, but those are things to look into.

I'm on E5-Xeon. What means io hub?

Stefan