Re: [libvirt] [Qemu-devel] Modern CPU models cannot be used with libvirt

On 03/12/2012 10:19 PM, Ayal Baron wrote: > > > ----- Original Message ----- >> On 03/12/2012 02:12 PM, Itamar Heim wrote: >>> On 03/12/2012 09:01 PM, Anthony Liguori wrote: >>>> >>>> It's a trade off. From a RAS perspective, it's helpful to have >>>> information about the host available in the guest. >>>> >>>> If you're already exposing a compatible family, exposing the >>>> actual >>>> processor seems to be worth the extra effort. >>> >>> only if the entire cluster is (and will be?) identical cpu. >> >> At least in my experience, this isn't unusual. > > I can definitely see places choosing homogeneous hardware and > upgrading every few years. > Giving them max capabilities for their cluster sounds logical to > me. > Esp. cloud providers. they would get same performance as from the matching "cpu family". only difference would be if the guest known the name of the host cpu. > >> >>> or if you don't care about live migration i guess, which could be >>> hte case for >>> clouds, then again, not sure a cloud provider would want to >>> expose >>> the physical >>> cpu to the tenant. >> >> Depends on the type of cloud you're building, I guess. >> > > Wouldn't this affect a simple startup of a VM with a different CPU > (if motherboard changed as well cause reactivation issues in > windows and fun things like that)? that's an interesting question, I have to assume this works though, since we didn't see issues with changing the cpu family for guests so far.