Got it! As per: http://www.linux-kvm.org/page/Hotadd_pci_devices You need to load the acpiphp kernel module: [root at localhost ~]# modprobe acpiphp (I could not find pci_hotplug, but it worked without it) If you then add a new disk from virsh: virsh # attach-disk 9 /dev/mapper/vg_alma_fast-lv_test_virtlvm2 vdb Disk attached successfully It is automatically detected: [root at localhost ~]# ll /dev/vdb brw-r----- 1 root disk 253, 16 Feb 10 16:26 /dev/vdb I could then extend the guest's LVM: [root at localhost ~]# pvcreate /dev/vdb Physical volume "/dev/vdb" successfully created [root at localhost ~]# vgextend VolGroup00 /dev/vdb Volume group "VolGroup00" successfully extended [root at localhost ~]# lvextend -l +100%FREE /dev/VolGroup00/LogVol00 Extending logical volume LogVol00 to 6.84 GB Logical volume LogVol00 successfully resized Thanks a lot for your help!! For reference, here are two interesting posts from the CentOS mailing list which are related to this topic: - Similar procedure (with Xen): LVM on both host and guest and adding additional space as disks: http://lists.centos.org/pipermail/centos-virt/2009-September/001161.html - Extending LVMs (a bit dated): http://lists.centos.org/pipermail/centos/2005-November/013471.html