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Re: [Xen-devel] Is QoS of virtual disk not necessary?

To: Satoshi Uchida <s-uchida@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Is QoS of virtual disk not necessary?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Wed, 22 Aug 2007 13:39:43 +0100
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Thread-topic: [Xen-devel] Is QoS of virtual disk not necessary?
User-agent: Microsoft-Entourage/
First impression was a lot of plumbing and not much in the way of moving
parts. Also of course we have CFQ on Linux -- I suspect the kinds of changes
you are suggesting would not be popular with kernel maintainers since they
will argue there is already an I/O scheduling subsystem. :-)

On the other hand, if you want to run a block driver in a driver domain (and
so outside dom0) then having a programmatic scheduling interface via
xenstore is quite nice...

 -- Keir

On 22/8/07 10:32, "Satoshi Uchida" <s-uchida@xxxxxxxxxxxxx> wrote:

> Hi,
> I sent RFC and a patch-set of I/O framework for virtual disk in order to
> introduce QoS in end of July.
>> http://lists.xensource.com/archives/html/xen-devel/2007-07/msg00863.html
> But no one responded to it.
> I think that when many virtual machines run on one physical machine, QoS of
> machine resources will be necessary.
> For example, in server consolidation, integrated servers have various roles
> and are different in the desired resources.
> So, distribution of resources is very important for stabilization.
> As other example, it will be avoided to be affected by jobs of other people in
> consolidation of office platform.
> CPU and memory are controlled (allocated) at Xen hypervisor. (This is OS
> agnostic)
> Is similar controller for I/O not necessary?
> Linux adopts CFQ which is fair scheduler which is suitable for desktop system.
> But, privileged domain will be not only Linux in future.
> I think that such function should be developed in Xen hypervisor or virtual
> block driver framework.
> Does anyone have opinions or idea?
> Please reply comments.
>  --------------------------------------------------
>  Satoshi UCHIDA 
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