Yes exactly, there is a hard limit on the number of socket Windows supports. For instance for a Windows 7 the max is 2 and for Windows Server 4 (except for the data center edition that has a higher limit).
With the current implementation, if you set 8 vcpu, Windows will only use 2 on a windows 7 VM. It currently means that creating a windows VM with a good level of performance with Cloudstack + KVM is not really possible. We are keen to help with the implementation of this feature for KVM however we would like to make sure that nothing else is in the pipe regarding the management of vCPU and core in service offering. I think that this will also be usefull to contol it from Cloudstack for VMware, and Xen (I don't know if this is possible with Xen). On Tue, Nov 19, 2013 at 12:10 AM, Edison Su <edison...@citrix.com> wrote: > Certain Windows server hard code on how many sockets it supports: > http://www.openwebit.com/c/how-to-run-windows-vm-on-more-than-2-cores-under-kvm/ > > > -----Original Message----- > > From: Chiradeep Vittal [mailto:chiradeep.vit...@citrix.com] > > Sent: Monday, November 18, 2013 1:53 PM > > To: dev@cloudstack.apache.org > > Subject: Re: Windows support for KVM > > > > I don't really understand the issue. > > What is the difference between > > <vcpu>8</vcpu> > > > > and > > > > <vcpu>1</vcpu> > > <cpu> > > <topology sockets='1' cores='8' threads='1'/> </cpu> > > > > > > Why does Windows see only 4 cores in the first case? Is it because the 8 > > cores are split across physical sockets? > > > > > > On 11/18/13 6:55 AM, "Arnaud Gaillard" <arnaud.gaill...@xtendsys.net> > > wrote: > > > > >Hello, > > > > > >A few days ago I created a new Jira ticket for the support of topology > > >in network offering for KVM. This is needed in order to support Windows > > >VM in KVM (currently the limitation are such that it is not really > > >possible to deploy real Windows VM with this configuration). > > > > > >The JIRA is > > >CLOUDSTACK-5071<https://issues.apache.org/jira/browse/CLOUDSTACK- > > 5071> > > >and > > >is refering to a bug opened before: > > >CLOUDSTACK-904<https://issues.apache.org/jira/browse/CLOUDSTACK- > > 904> > > >. > > > > > >As I have received no comment on it, I would like to know if the > > >support of topology in service offering was considered as a priority, > > >and if the impact on the GUI was studied? > > > > > >Cheers! > > -- *Arnaud Gaillard* CTO Mobile : +41 78 674 58 95 <https://docs.google.com/file/d/0B2iGziD9SUPURU0yRjhSX1JhU0k/edit?usp=sharing>
