[virt-tools-list] Live Migration of KVM VMs

[Phil Meyer]

We are running RHEL-5.5 hosts.
All VMs are KVM.
All VMs have dedicated iscsi targets.  Those targets are made multi-host 
and enabled on the target host prior to the migration.

Live migration from virt-manager running on my Fedora 13 desktop, does a 
live migration, and creates the domain.xml file on the target.  It 
leaves the domain.xml file on the original host, which needs to be 
undefined manually.

PROBLEM:
Running virsh directly on the command line, does NOT create the 
domain.xml file on the target host.

Staring for a while at the python scripts in the virt-manager source 
brought no inspiration.

Here is the command line used on my Fedora 13 desktop:

$ virsh -c qemu+ssh://root@172.20.1.1/system migrate --live --persistent 
--undefinesource 7659-centos-core qemu+ssh://root@172.20.1.16/system

Both of those hosts are RHEL-5.5

The version of virsh/libvirt on those hosts do not support --persistent 
or --undefinesource.

However, virt-manager seems to get --persistent to work or at least 
emulates that function somehow when communicating with hosts that have 
older versions of libvirt.

How does it do it?

Any help is appreciated.