Quoting "Gregory K. Ruiz-Ade" <[EMAIL PROTECTED]>:
anyone have a link that explains, for stupid people like me, the
differences between paravirt and full virt on xen, including all the
limitations of the two?
Quick and dirty (I might be wrong, but this is how I understand it):
- Paravirt - Now hw support required. Quest OSes must know they're
running inside paravirt host (i.e. linux with xen kernel). Has speed
advantages over full because it's basically like an OS inside
processes and so the main/dom0 install is basically just switching
processes. You also cannot cross bitness (i.e. no 32bit guest OS on
64bit dom0 OS.. yet anyway)
- Full virt - Requires HW support (i.e. AMD Pacifica or Intel VTx
extensions). Advantages are the guest OS doesn't even know it's being
virtualized. Disadvantage is more of a speed hit as the hw basically
has to context switch out all the info (registers and such) for each
switch between virtual hosts (vs the paravirt being done by OS).
I could be wrong on the speed diffs, but everything I've read is that
paravirt has a definite speed advantage (in most if not all cases) but
because the guest needs to know it's being paravirtualized, that's the
one big negative most people see. If you're only virtualizing linux
on linux, or any paravirtualizable OS.. then it's not a problem.
As a side note, I've had a host on slicehost for several months now
(basically my dns and MX server) that's nothing but a xen instance.
It's been rock solid and has performed beautifully. You'd never know
you weren't on your own box if you didn't know what the -xen in the
kernel meant.
--
Mike Marion-Unix/Linux Admin-http://www.miguelito.org
Commentator in "Triple Play Baseball" for PS2: "The key to scoring runs is
cashing in when you're in scoring position."
-- Thank you, Captain Obvious!
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