Re: How to use a file system image for Linux DomU ?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Aug 05, 2005 at 06:00:16PM +0200, Thierry Herbelot wrote:
> Le Wednesday 3 August 2005 12:54, Manuel Bouyer a écrit :
> > On Mon, Jul 25, 2005 at 07:22:26PM +0200, Thierry Herbelot wrote:
> >
> > I admit I never tried to start a linux-2.4.x kernel from NetBSD dom0.
> > linux-2.6.x works fine for me.
> 
> it works, at least on "physical-disk" configurations (will check on vn0d 
> domains)
> >
> > OK, this is known problem with the NetBSD xbd backend, which should be
> > fixed now. Try to update to a more recent NetBSD kernel (newer than 07/19
> > on current).
> 
> indeed, I just checked with the Xen0 kernel from the 200508030000Z snapshot 
> (as I only changed the kernel without upgrading the userland, I'm a bit 
> worried about incompatibilities ? is it a "normal" way to run a NetBSD 
> machine ?)

If both are from the netbsd-3 branch it shouldn't be much of a problem
(exept if some subsystems with both kernel and userland part, such as
ipf, have been updaed).
You can expect more problems if you mix kernel and userland from different
branches, but the system should boot anyway as long as the kernel is
newer or from a newer branch than userland (e.g. netbsd-2 userland
with netbsd-3 kernel, or netbsd-3 userland with current kernel).

> I'm getting some error messages on the serial console :
> xbdback: domain 2 sending excessively fragmented I/O
> 
> Is this something to be afraid of ?

It should not cause problems. If I understand it, this means that the
domain sent a request with adgacent segments which could be merged in
a single one. This just means that this domain's kernel could generate
more efficient requests.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--