I had similar issues on Ubuntu 15.10. I’ve downgraded Qemu to 2.1. Now it works like a charm.

 

 

Van: libvirt-users-bounces@redhat.com [mailto:libvirt-users-bounces@redhat.com] Namens Keyur Bhalerao
Verzonden: maandag 7 december 2015 21:53
Aan: libvirt-users@redhat.com
Onderwerp: [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/