Re: [libvirt-users] setvcpus libvirt 1.2.9

On 11/05/2014 01:20 PM, Thomas Stein wrote: > Am 05.11.14 11:48, schrieb Martin Kletzander: >> On Wed, Nov 05, 2014 at 11:35:37AM +0100, Thomas Stein wrote: >>> Hello. >>> >>> I'm struggeling a little bit with the setvcpus command. I'm trying now >>> to get this running for a linux VM. Here is what i have: >>> >>> <vcpu placement='auto' current='2'>4</vcpu> This is one case where xen may be a bit more powerful than current qemu support. Xen supports booting a guest with a promise of a maximum cpu larger than what it boots with; but I don't know that qemu does that well yet. For now, with qemu, you pretty much have to boot with all cpus enabled, then after the guest is up and running, disable the cpus you don't plan to use right away. CPU hotplug/hot-unplug is still a work in progress in qemu (for example, some versions of qemu support hotplug but not hot-unplug). I haven't played much with it myself to know what minimum version of libvirt and qemu will do what you want, so you may have to do some experimentation.