#==================================================#
root@~$ virsh list
 Id    Name                           State
----------------------------------------------------
 8     vm1-f17                        running

root@~$ 
#==================================================#
root@~$ virsh domblklist vm1-f17
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/vm1-f17.qcow2

root@~$ 
#==================================================#
root@~$ virsh dumpxml --inactive vm1-f17 > /var/tmp/bc-test.xml
root@~$
#==================================================#
root@~$ diff /etc/libvirt/qemu/vm1-f17.xml /var/tmp/bc-test.xml
1,7d0
< <!--
< WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE 
< OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
<   virsh edit vm1-f17
< or other application using the libvirt API.
< -->
< 
55a49
> 
root@~$ 
#==================================================#

NOTE1 : Currently due to QEMU's limitation, libvirt expects a domain to be trasient. Because, blockcopy jobs last forever until canceled, which implies that they should last across domain restarts if the domain were persistent. But qemu doesn't yet provide a way to restart a copy job on domain restart. So the trick is to temporarily make the domain transient

NOTE 2: Undefining a running domain does not KILL the domain, it just converts it from persistent to transient
#==================================================#
root@~$ virsh undefine vm1-f17
Domain vm1-f17 has been undefined

root@~$
#==================================================#
root@~$ virsh list
 Id    Name                           State
----------------------------------------------------
 8     vm1-f17                        running

root@~$ 
#==================================================#

#==================================================#
root@~$ file /etc/libvirt/qemu/vm1-f17.xml
/etc/libvirt/qemu/vm1-f17.xml: ERROR: cannot open `/etc/libvirt/qemu/vm1-f17.xml' (No such file or directory)
root@~$ 
#==================================================#
root@~$ virsh blockcopy --domain vm1-f17 vda /export/backups/vm1-f17-copy.qcow2 --wait --finish --verbose
Block Copy: [100 %]
Successfully copied
root@~$ 
#==================================================#
root@~$ virsh define /var/tmp/bc-test.xml 
Domain vm1-f17 defined from /var/tmp/bc-test.xml
#==================================================#
root@~$ file /etc/libvirt/qemu/vm1-f17.xml
/etc/libvirt/qemu/vm1-f17.xml: exported SGML document, ASCII text
root@~$ 
#==================================================#
root@~$ sha1sum /var/lib/libvirt/images/vm1-f17.qcow2 ; sha1sum /export/backups/vm1-f17-copy.qcow2 
3ae5c64f06ba0059f2c0628e20092b3797f08275  /var/lib/libvirt/images/vm1-f17.qcow2
3ae5c64f06ba0059f2c0628e20092b3797f08275  /export/backups/vm1-f17-copy.qcow2
root@~$ 
#==================================================#