Re: [Xen-users] disk speed

["Sebastian Reitenbach" <sebastia@xxxxxxxxxxxxxxxxxxxx>]

Hi Dan,

"Dan VerWeire" <dverweire@xxxxxxxxx> wrote: 
> Are you using PV or HVM DomU's? If HVM, this may be expected as the block
> device presented to the DomU is an emulated device in Dom0. Someone 
correct
> me if I am wrong please.
> 
thanks for your insights. I am running paravirtualized machine, so if I 
understand correct, I should get sth. different?

Sebastian

> Dan
> 
> On 10/22/07, Sebastian Reitenbach <sebastia@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > I started to experiment with xen, so I am still new to it. I was 
impressed
> > how easy I got my first virtual node up and running.
> > I measured the disk speed, created a 1gb file with dd.
> > copying that file on the dom0 always took about 5 seconds, on the domU, 
it
> > took about 15-20seconds. I used "time cp large_file large_file2" to
> > measure
> > the speed. I only expected a small time difference, but not factor 3-4.
> > My virtual disk is a physical device, configured like this:
> > disk=[ 'phy:/dev/sdv2,xvda,w', ]
> >
> >
> > As far as I know, using the physical partitions as the virtual disk,
> > should
> > be the fastest solution for virtual disks, compared to files.
> >
> > Are there different ways to present a physical partition from dom0 to a
> > domU, that would influence the speed? Or is the speed factor I have seen
> > above the one to expect?
> >
> > I am on sles10sp1 x86_64.
> >
> > kind regards
> > Sebastian
> >


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