Re: [Xen-users] disk IO profiling in guest suing sar command

[Iain Kay <spam@xxxxxxxxxxx>]

Hey Steven,

I'd certainly imagine you need to run the tool on the guest to get an accurate 
reading.

From what I've seen of xen boxes dom0 is running like a domU and only reporting 
loads/usage of the host node itself. Not the guests.

I could be wrong, but this is what I make of it.

Iain Kay


On 18 May 2011, at 21:43, Steven wrote:

> Hi,
> I am trying to profiling disk IO caused by page miss in memory inside
> a guest OS. Both guest and host OS are Fedora 13.
> I am using the linux command sar which provide such number of major faults 
> like
> 
>        majflt/s:
>                   Number of major faults the system has made per
> second, those which have required loading a memory page from disk
> 
> Then I started a workloads on both the guest and host OS. As a result,
> the guest reports about 1000 majfits, while the host reports only
> around 80. So is 1000 majflt is the actual disk IO for that guest? Or
> the number of host OS is what I want. Thanks.
> 
> - w
> 
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