Thanks for your help. Ok, I didn't understand how to use "cpu-baseline", it's not clear in the help command. So "cpu-baseline" give me the CPU XML file I need to use to be able to migrate between two hosts but how I use this XML file ? Another question, why Libvirt consider CPUs with non-matching vendors cannot be compatible ? Doude. On Tue, Mar 22, 2011 at 3:01 PM, Jiri Denemark <jdenemar@xxxxxxxxxx> wrote: > On Mon, Mar 21, 2011 at 18:34:40 +0100, Edouard Thuleau wrote: >> Hi, >> I try to understand the compare and baseline CPU commands with libvirt. >> This functions are useful for the migration ? Before migrate a domain to >> other host, libvirt verifies the CPU compatibility, that's right ? > Right. > >> > *$ virsh cpu-baseline cpu_gargamel.xml * > > It's not clear what the content of cpu_gargamel.xml is. Does it contain CPU > definitions from both hosts? virsh cpu-baseline is supposed to give you an > intersection of the CPUs given in the XML file; it doesn't use host CPU on > which this command is called. > > If you take the two host CPUs above, remove <vendor> elements (since CPUs with > non-matching vendors are considered incompatible), and pass that to > cpu-baseline, you will get the following guest CPU which you can use to be > able to migrate between the two hosts: > > <cpu match='exact'> > <model>Opteron_G2</model> > <feature policy='require' name='ht'/> > <feature policy='require' name='vme'/> > <feature policy='disable' name='svm'/> > <feature policy='disable' name='rdtscp'/> > </cpu> > > Note, that there is no <vendor> element there since mentioning vendor in guest > CPU config means that you always want to run the domain on CPUs from this > specific vendor and migrating it to another vendor will fail. > > Jirka > > -- > libvir-list mailing list > libvir-list@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/libvir-list > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list