ZFS with multiple boot/root pools

[Martin Simmons]

>>>>> On Wed, 02 May 2012 08:50:22 +0100, Matthew Seaman said:
> 
> On 02/05/2012 06:28, Peter Jeremy wrote:
> 
> >> >http://www.infracaninophile.co.uk/articles/install-on-zfs/ but there are
> >> >several other treatments around.
> 
> > I've had a look through those notes and you are still specifying
> > mountpoints for (eg) zroot/ROOT/9.0-RELEASE/usr - which implies you
> > wind up with multiple /usr's mounted.  
> 
> Yes.  That's deliberate, and /usr is treated as a special case, because
> I want to keep instances /usr/src and /usr/obj paired up with the BE
> built from them, and it makes things a lot easier if I can mount them
> early at /usr/src or /usr/obj in order to do the build.

It looks like /usr itself isn't a problem because it is never mounted
(canmount=off on zroot/ROOT/9.0-RELEASE/usr and zroot/usr), but multiple
mounts will happen for /usr/src and /usr/obj.  Do you change the mountpoint
property of zroot/ROOT/*/usr on the inactive BE's to avoid that?

BTW, there is a minor bug in the article (on 8.3 at least): "zpool export
zroot" fails to unmount everything because the cwd is in /tmp/zroot/etc at
that point.  Adding "cd /" beforehand fixes it.

__Martin