How to use DFly sources via nfs?

[YONETANI Tomokazu]

On Sat, Jun 05, 2004 at 09:08:51AM -0700, walt wrote:
> Joerg Sonnenberger wrote:
> 
> >That's exactly the kind of problem I meant. It does not happen with union 
> >or
> >null mounts...
> 
> I just read the manpage on mount_null and I'm feeling a bit dizzy ;o)
> 
> Are you suggesting that mount_null could really be used in an everyday,
> practical way to share the /usr/src directory?
> 
> If yes, an example would be very helpful.

Just FYI, on one of my DragonFly box, /usr/obj (and of course
MAKEOBJDIRPREFIX points to /usr/obj) is null-mounted from /var/obj and
it always survives make -j 3 buildworld.
As for mount_union, on the other hand, everything works as expected
until you touch something in the lower layer. I've never used it for
building kernel/world though.