> 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 ? You can just stick the output of cpu-baseline to guest's XML file, so you could have something like the following: <domain type='kvm'> <name>domain-name</name> <memory>262144</memory> <currentMemory>262144</currentMemory> <vcpu>2</vcpu> <os> <type arch='x86_64' machine='pc-0.12'>hvm</type> <boot dev='cdrom'/> </os> <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> ... </domain> > Another question, why Libvirt consider CPUs with non-matching vendors > cannot be compatible ? That's because CPUs made by different vendors are not generally compatible. Migration between them may work but it's not guaranteed. Libvirt allows you to choose whether you want to stick with a single CPU vendor or not. If you put <vendor> tag into the <cpu> element above, libvirt will forbid migration to a CPU made by a different vendor. If no <vendor> tag is present, CPU vendor is not checked during migration. Jirka -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list