Re: The concept of DomU.

[Andy Smith <andy@xxxxxxxxxxxxxx>]

Hello,

On Sun, Aug 23, 2020 at 07:14:14AM +0000, Jason Long wrote:
> Excuse me, Xen Project running 100 guest OSes. How many DomU running?

In the usual case, at most 99. What is not clear about this?
Without understanding where you aren't following all I can do is
repeat what Bernd and I have already typed.

A Xen system normally requests a dom0, which is a domain; it is a
guest, it runs a guest OS like Linux or NetBSD.

Your question as posed says only "guests", which in Xen terminology
is "domain", and dom0 is a domain. So with 100 domains, on most Xen
setups that would mean 99 domU and 1 dom0.

However it seems like what you really meant is, "100 unprivileged
domains". Since a domU is an unprivileged domain that question reads
as "I'm running 100 domUs. How many domUs am I running?"

The thing you are maybe not getting is that dom0 is a guest, like
all the other guests, except that it has extra privileges. It is
still a virtualized OS like all the other ones on the hypervisor.

Cheers,
Andy