[libvirt] inability to open local read-only connection

[Tavares, John]

When I was using libvirt directly, I did see that, but could never make it work.  This is some of the additional memory/performance information we would be interested in.  In the event I stick with using virsh, it is available it as well as I have yet to see it??

-----Original Message-----
From: Daniel P. Berrange [mailto:berrange at redhat.com] 
Sent: Friday, August 20, 2010 10:30 AM
To: Tavares, John
Cc: Justin Clift; libvir-list at redhat.com
Subject: Re: [libvirt] inability to open local read-only connection

On Fri, Aug 20, 2010 at 09:15:04AM -0500, Tavares, John wrote:
> Should the memory utilization as report from inside a guest match that 
> as reported by the hypervisor??  I think one of my QA engineers may have
> pointed out a Windows guest where this was not the case.

It depends what libvirt APi you are referring to when you talk about
memory utilization. virDomainGetInfo returns data about the memory
allocated to the guest by the hypervisor. This says nothing about
what the guest OS is doing with the memory. eg, the guest has been
given 500 MB, but its OS may have only used 200 MB so far.

We have a fairly new API virDomainGetMemoryStats that can give info
about how much of its allocated memory a guest has actually used,
along with stats on swap in/out and major/minor fails. This is only
implemented for KVM + virtio though and requires a guest with a pretty
new balloon driver to report the data


Daniel
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