Re: [Xen-users] differences between Para-Virtualization and Full-Virtualization?

Nico Kadel-Garcia
Fri, 20 Jul 2007 08:44:33 -0000

Songtao Liu wrote:
> Hi,
>
> Could someone explain me the following questions:
>
> Where are differences between Para-Virtualization and Full-Virtualization
in the aspects of memory management, CPU and Device I/O, Network?
>
> How is the performance difference between them?
>
> Thanks
> Songtao
There are dozens of good documents on this. Boiled down to a few lines,
full virtualization emulates the entire hardware platform of a guest
computer. That can be effective for running an otherwise incompatible
operating sytem, like Windows on a Linux server.

Para-virtualization uses a customized kernel, compatible with the
host''s
kernel and "hypervisor", that speaks compatibly and much more directly
to your host''s hardware. It''s much lighter weight, allows
memory to be
re-allocated among guest domains so a server can run far more guest
domains,, and provides a really noticeable to any guest operation that
has to talk to the disk. But it requires a compatible kernel on the
guest OS, compatible with the Xen version of the host OS.