Description of problem: Currently, virtual disks (volumes) are created in "raw" format. Since "qcow2" is the native format and since it makes more efficient use of space (IMHO), this should be the default. Version-Release number of selected component (if applicable): F11 + preview
Given http://fedoraproject.org/wiki/Features/KVM_qcow2_Performance this might not be unreasonable One problem mentioned by danpb is that we can't pre-allocate a qcow2 image - AFAIR, we do that so that guests don't run out of space at some point in the future when the guest runs out of space. There may also have been a performance reason for doing it, too. Anyway, if we do change the default to qcow2, I don't think we'll do it until Fedora 13, so putting it on F13VirtTarget.
There's a whole lot to this equation, and outright changing the default is a ways off: for starters we want to at least allow users to change the default manually. Basically tracking this in a simple BZ isn't that useful so just closing.