Live backup of your VM running in KVM under Ubuntu using qcow2 disk images

# First of all disable apparmor to allow access

aa-status

aa-complain /usr/sbin/libvirtd

aa-complain /etc/apparmor.d/libvirt/libvirt-xxxxxxxxxxxxxxxxxx

# View disks

virsh domblklist test-backup

# Suspend the domain (This is optional. I do this so that the condition of virtual machines remains unchanged during the backup.)

virsh suspend test-backup

# Create snapshot

virsh snapshot-create-as --domain test-backup test-snap1 \

--diskspec vda,file=/home/virtual/test_backup/test-c.img \

--diskspec vdb,file=/home/virtual/test_backup/test-d.img \

--disk-only --atomic

# or

virsh snapshot-create-as --domain test-backup test-backup-snap1 --disk-only --atomic

# View snapshots

virsh snapshot-list test-backup

# View disks (it must be running on snapshots)

virsh domblklist test-backup

# Copy drives to backup dir

rsync -avh --progress drive-c.qcow2 export/drive-c.qcow2-copy

rsync -avh --progress drive-d.qcow2 export/drive-d.qcow2-copy

# Perform active blockcommit by live merging contents

virsh blockcommit test-backup vda --active --verbose --pivot

virsh blockcommit test-backup vdb --active --verbose --pivot

# View disks (it must be running on normal drives)

virsh domblklist test-backup

# Unsuspend the domain

virsh resume test-backup

# View snapshots again

virsh snapshot-list test-backup

# Delete snapshots

virsh snapshot-delete test-backup test-backup-snap1 --metadata

# View snapshots to check 

virsh snapshot-list test-backup

# Delete snapshot files

rm -f /home/virtual/test_backup/drive-c.test-backup-snap1

rm -f /home/virtual/test_backup/drive-d.test-backup-snap1