Re: recommendations for a Xen/NetBSD box?

[Luke S Crawford <lsc%prgmr.com@localhost>]

Carl Brewer <carl%bl.echidna.id.au@localhost> writes:
> So if you were going to build a Xen server to host a NetBSD 4.0 (i386)
> production (ie: must be stable!) DomU and a couple of others as
> development/play domU's, what would you suggest as the Dom0 and what
> version of Xen should I be looking at?

Your trouble is NetBSD/i386 -stable only runs in non-PAE mode (if you
are cool with -current, there is PAE support for DomU)   and the
PAE mode of the Dom0 and the DomU must match.

CentOS (and I think most distros) assume your xen kernels are PAE.  
so if i386 is essential, you will need to re-compile all your Linux
kernels to disable PAE (it works fine, and it's stable;  it's just
kindof a pain, because you don't get binary updates)  

Your problem is solved if you are cool with runing on x86_64 (your
chip will support it)  if you make a 64-bit Dom0, if you use xen 3.1, 
32-on-64 should work for linux/PAE-i386 DomUs, but 32-on-64 is really 
32PAE-on-64, so it still won't get you i386 NetBSD DomUs)

But yeah,  if you want i386, you are either running NetBSD-current or
you are running the whole box non-pae.  Running the whole thing in
x86_64 is really quite a lot easier.


(oh, and a note, the hypervisor is the xen.gz kernel you see in your 
grub config;  it is what sits in ring0;  it mediates access to the cpu,
to ram, and (loosly) the pci bus.   all other domains
run under the hypervisor.  the Dom0 is a privliged guest domain that has
access to send control statements to the hypervisor, and that has access
to the PCI bus.  The Dom0 will access real hardware and present 
xen disk and network devices to the hypervisor;  the hyperviosor then passes
those virtual devices out to the unprivliged domains, the DomU.)