This attached patch resolves a fairly obvious problem which stops qemuDomainMemoryPeek from working at all. However, it's not the whole story. Read on ... (1) qemu still fails unless I manually set the mode of /var/cache/libvirt to 0755 (it is normally 0700). Owner Fails Works /var/cache/libvirt root.root 0700 0755 /var/cache/libvirt/qemu qemu.qemu 0750 0750 qemu is doing: open("/var/cache/libvirt/qemu/qemu.mem.fdVCod", O_WRONLY|O_CREAT|O_TRUNC, 0666) It's kinda annoying that /etc/libvirt and /var/{cache,lib}/libvirt are unreadable by other users. Is there some deep reason to do this? (2) After applying this patch, using virDomainMemoryPeek causes libvirtd to generate the following serious-looking warning. It doesn't appear to crash or fail in any way that I can tell: 15:17:09.982: 7784: error : virDomainFree:2122 : invalid domain pointer in virDomainFree I don't know where this is coming from. It only appears when my program actually does virDomainMemoryPeek, not when I have the same code with virDomainMemoryPeek commented out. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://et.redhat.com/~rjones/virt-top