Hi, On a KVM host installed with following packages versions : [root@rhel6-roadster test_channels_OK]# rpm -qa | grep libvirt libvirt-devel-0.10.2-29.el6.x86_64 libvirt-0.10.2-29.el6.x86_64 libvirt-client-0.10.2-29.el6.x86_64 libvirt-java-0.4.9-1.el6.noarch libvirt-java-devel-0.4.9-1.el6.noarch libvirt-python-0.10.2-29.el6.x86_64 [root@rhel6-roadster test_channels_OK]# rpm -qa | grep qemu qemu-kvm-0.12.1.2-2.415.el6.x86_64 gpxe-roms-qemu-0.9.7-6.10.el6.noarch qemu-img-0.12.1.2-2.415.el6.x86_64 [root@rhel6-roadster test_channels_OK]# virsh --version 0.10.2 [root@rhel6-roadster test_channels_OK]# When trying to add a channel device via virsh attach-device , I got following errors : <channel type='unix'> <source mode='bind' path='//var/lib/libvirt/qemu/omnivision_123456.agent'/> <target type='virtio' name='omnivision_123456.agent' state='disconnected'/> <alias name='channel_OmniVision'/> <address type='virtio-serial' controller='0' bus='0' port='30'/> </channel> Guest is off : [root@rhel6-roadster test_channels_OK]# virsh attach-device Linux_2 add_channel_device.xml error: Failed to attach device from add_channel_device.xml error: Requested operation is not valid: cannot do live update a device on inactive domain [root@rhel6-roadster test_channels_OK]# Guest is running : [root@rhel6-roadster test_channels_OK]# virsh attach-device Linux_2 add_channel_device.xml error: Failed to update device from add_channel_device.xml error: XML error: unknown device type [root@rhel6-roadster test_channels_OK] Did I miss something ? Thanks for help. J.P. Ribeauville P: +33.(0).1.47.17.27.87 Puteaux 3 Etage 5 Bureau 4 jpribeauville@axway.com<mailto:jpribeauville@axway.com> http://www.axway.com<http://www.axway.com/> P Pensez à l'environnement avant d'imprimer.