On Thu, Apr 22, 2010 at 11:07:17AM -0400, Yufang Zhang wrote: Assuming you mean virtio block devices (not network), then the default was changed from ide to virtio in this commit: http://git.annexia.org/?p=libguestfs.git;a=commitdiff;h=6c97a65ce768b357a... The first release containing this change was 1.0.84. However, it's a little bit more complicated than that. Packagers can choose whether or not to enable virtio at configure time: ./configure --with-drive-if=(ide|virtio|scsi) So it's possible that a particular RPM with version >= 1.0.84 might still be using IDE. In fact it's even a bit more complicated than that. It's also possible to override this *at runtime*. I believe for some reason virt-v2v does this, forcing the IDE driver always. The only way to find out what block device is really being used is to run verbose (LIBGUESTFS_DEBUG=1) and look at the parameters passed to qemu, eg: [...] /usr/bin/qemu-kvm \ -drive file=/tmp/test,cache=off,if=virtio \ [...] ^^^^^^ means using virtio-blk BTW it *should* make no difference which driver is being used, although in reality different bugs in QEMU and the kernel can end up biting you in different ways. Don't use Fedora 11 or libguestfs 1.0.72. Those versions are ancient :-) Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming blog: http://rwmj.wordpress.com Fedora now supports 80 OCaml packages (the OPEN alternative to F#) http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora