[OpenIndiana-discuss] nfs mounting and cascading dataset access?

[James Carlson]

Scott LeFevre wrote:
> I have a pools setup named tank1 with multiple datasets/filesystems
> defined.  At the top, I have tank1/media followed by tank1/media/Video
> and tank1/media/Music.  I've setup tank1/media as a nfs share
> (e.g. /export/media) and can mount it from other systems.  When I try to
> access media/Video from the nfs client, it shows an empty directory.
> (From the oi 151a2 host, everything shows up locally.)   I can mount
> tank1/media/Video directly from the nfs client and everything shows up
> as it should.  
> 
> Is there a way to make this work where I expose just tank1/media as an
> nfs export and can access the underlying datasets/filesystems (e.g.
> Video and Music)?

This isn't really a special issue with ZFS.

NFS has always done exports by file system.  If you have /foo and
/foo/bar, and /foo/bar is a mount point for some other file system, then
exporting /foo does not give clients access to the contents of /foo/bar,
because there's no way to cross the file system boundary.  Instead,
clients looking at /foo/bar will see there whatever is actually in the
/foo file system -- probably just an underlying empty directory used as
the mount point.

What you can do is set "sharenfs=on" (or some list of NFS options
instead of just "on") using the zfs command on tank/media, and all of
the filesystems under that point will inherit this setting.  That means
that clients will see separate NFS exports for each of the underlying
datasets -- one for Video and one for Music in this case.

Automount, of course, is your friend.  ;-}

-- 
James Carlson         42.703N 71.076W         <carlsonj at workingcode.com>