[libvirt-users] Efficient live disk backup with active blockcommit : Failed 'block-commit': Could not reopen file: Permission denied

Hi , Working on the simple POC : Advanced snapshot using libvirt and qemu . Following are the exact steps which are followed . 1. Created as base VM - Ubuntu 15.10 with following libvirt and qemu versions Using library: libvirt 1.2.16 Using API: QEMU 1.2.16 Running hypervisor: QEMU 2.3.0 QEMU emulator version 2.3.0 (Debian 1:2.3+dfsg-5ubuntu9.1), Copyright (c) 2003-2008 Fabrice Bellard 2.Created nested VM (vm-01) using VirtManager on base VM. 3.Used following commands to take the multiple snapshots - virsh # list Id Name State ---------------------------------------------------- 7 vm-01 running virsh # domblklist vm-01 Target Source ------------------------------------------------ vda /home/ubuntu/vm-01.img hda /dev/sr0 snapshot-create-as --domain vm-01 snap1 --diskspec vda,file=/var/lib/libvirt/sn1.qcow2 --disk-only --atomic snapshot-create-as --domain vm-01 snap2 --diskspec vda,file=/var/lib/libvirt/sn2.qcow2 --disk-only --atomic virsh #snapshot-list vm-01 ------------------------------------------------------------ snap1 2015-12-07 11:51:51 -0800 disk-snapshot snap2 2015-12-07 11:52:28 -0800 disk-snapshot virsh # snapshot-list vm-01 --tree snap1 | +- snap2 List the current block device in use, again. It can be noticed, the new overlay 'sn2.qcow2' is the current disk in use: virsh # domblklist vm-01 Target Source ------------------------------------------------ vda /var/lib/libvirt/sn2.qcow2 hda /dev/sr0 Now that the backup is finished, perform active blockcommit by live mergning contents of sn2 into base: ubuntu@keyurubuntu:~$ virsh blockcommit vm-01 vda --active --verbose --pivot error: internal error: unable to execute QEMU command 'block-commit': Could not reopen file: Permission denied I am not sure why this is getting as permission denied. I have tried couple of times reinstalling and creating new VMs . Every time when i have tried to block-commit getting landed into same error. Is there any troubleshooting or solution to this issue. Stuck on this issue for last 2 days. Quick help much appreciated. Thanks, Keyur Bhalerao Reference used - http://wiki.libvirt.org/page/Live-disk-backup-with-active-blockcommit - http://kashyapc.com/2012/09/14/externaland-live-snapshots-with-libvirt/