Xen?

Posted Dec 10, 2009 4:29 UTC (Thu) by ncm (guest, #165)
Parent article: FreeBSD 8: an evolutionary release of the unknown giant

I'm curious about their integrating Xen at the same time as Linux seems to
be abandoning it. Should we assume that FreeBSD runs as a guest under KVM
with no adaptions needed?

Xen?

Posted Dec 10, 2009 7:10 UTC (Thu) by drag (guest, #31333) [Link] (3 responses)

Xen requires kernel modifications in the guest operating system in order to
take advantage of 'paravirtualization', which has dramatic speed
improvements.

KVM does not use this approach and does 'full virtualization' with the
assistance of hardware virtualization features. This allows operating
systems to run as guests unmodified. (Xen can go full virt with similar
hardware support)

Xen?

Posted Dec 10, 2009 20:23 UTC (Thu) by elanthis (guest, #6227) [Link] (2 responses)

Correct me if I'm wrong, but KVM allows paravittualizatuon as well, for guests that support
it's interface, letting it achieve similar performance to xen for (currently) Linux guests.

Windows paravirt guests under kvm

Posted Dec 11, 2009 15:51 UTC (Fri) by mcmanus (guest, #4569) [Link]

You can run paravirt network and block i/o on windows guests (as well as the aforementioned linux guests) under kvm hosts if you like: http://www.linux-kvm.org/page/WindowsGuestDrivers/Downloa...

Xen?

Posted Dec 11, 2009 15:55 UTC (Fri) by gnb (subscriber, #5132) [Link]

Yes, you can use paravirtualised device drivers in KVM to avoid the I/O
performance hit of emulated I/O hardware for things like networking and
disks. That said the guest kernel is unmodified, so it won't run at all
without CPU virtualisation support, and some aspects of kernel performance
will be very dependent on how good the implementation of said support is in
the CPU you're using.