Journalctl -u libvirtd

journalctl -u libvirtd | grep -i error

libvirtd[14189]: 2019-11-21 15:08:13.035+0000: 14192: error : qemuDomainBlockCommit:17568 : invalid argument: top '/path/to/file/VM_NAME.qcow2' in chain for 'hda' has no backing file

See also

• KVM, Installation, QEMU, virsh, virtinst, libguestfs-tools, libvirt, qemu, Red Hat Virtualization (RHV), MacVTap, Virtio, oVirt, KVM services, KVM networking, KVM graphics, CPU, KVM on ARM