Uma coisa muito importante que foi anunciado no Red Hat Summit: a Red hat está adotando o KVM como hypervisor para virtualização, em detrimento do Xen:

http://news.cnet.com/8301-13556_3-9973661-61.html

As razões citadas:

“Red Hat’s been a fan of KVM for a while. There are a couple of major reasons for this: one business, one technical. Both involve Xen, the Open Source hypervisor project that underpins most server virtualization on Linux today.

The business reason is that, while Red Hat contributes to and works on Xen, competitors are far more associated with the project. Novell, the owners of the only other major enterprise Linux distribution, ran especially hard with Xen early on. And Citrix–not a direct competitor but certainly a major virtualization player–bought XenSource, the commercial entity formed by Xen’s creators.

From a technical perspective, Red Hat’s issue is that it’s hard to keep Xen and the Linux kernel in sync. Xen’s a standalone hypervisor layer but it has deeply invasive hooks into the Linux kernel and, therefore, keeping the two working together takes a lot of development and testing effort. It’s a bit reminiscent of how new versions of the VERITAS filesystem had to be carefully matched to new versions of Solaris or HP-UX.

By contrast, KVM is kernel-based. This means that it is actually part and parcel of the Linux kernel rather than a quasi-independent piece of software.”