Comment 14 for bug 1449687

Just want to throw a comment on here too. We are also effected by this. We are in the process of switching to KVM and lose thin/sparse disks on live migration. Unfortunately we need this to work.

We are using:
* Ubuntu Xenial
* qemu-kvm version 2.5
* libvirt-bin version 1.3.1
* Using local storage

I've tried qcow2 and raw formats with files and even a thin LVM pool. We have had the same outcome every time.

virsh migrate --live --persistent --undefinesource --copy-storage-all (and --copy-storage-inc) fails to keep the sparse file.

I've had no luck using rsync or tar to pre-copy the disks either.

Building libvirt (v3.10.0) and qemu (v12.11) from source solved the issue but is not practical for us to do this in our environment. Using the repository above that Anthony mentioned is a temporary fix in my opinion, it's using libvirt v3.6.0 and qemu v12.10.1 and also solves the migration bug. Ubuntu should release a patch for Xenial. It appears Bionic will include the working versions.