[CentOS] XEN or KVM - performance/stability/security?

Tue Apr 24 03:43:17 UTC 2012
Dennis Jacobfeuerborn <dennisml at conversis.de>

On 04/24/2012 03:08 AM, John R Pierce wrote:
> On 04/23/12 5:12 PM, Dennis Jacobfeuerborn wrote:
>> The PVM/HVM distinction isn't really that relevant any more on modern
>> hardware and modern hypervisors since most of the overhead is eliminated
>> with hardware features (Nested Page Tables, etc.) and special guest drivers.
> "special guest drivers" is pretty much what paravirtualization is about.

Exactly, but only since CPU got hardware extensions for virtualization.
Before that the CPU could also be paravirtualized and that made a
significant difference in performance.

With that advantage gone though the old distinction between a "PVM guest"
and "HVM guest" doesn't really matter that much any more (virt-manager asks
you which of the two you want to install for example). Now you only have a
"guest" that may or may not run certain paravirtualized drivers.