[KLUG Members] An NFS design/use question...

[Adam Williams]

> What I'm doing may be equally complex in some ways, perhaps even intractable.
> Going back to the original question...
> mount nfs-one:/Users /home
> mount nfs-two:/shared/mail/joe /home/joe/mail
> If we assume that /Users/joe/mail on nfs-one is empty, then does the 
> second mount work? 

It should, regardless of /Users/joe/mail bieng empty.  Mounts are not
transparent.  Whatever was in /Users/joe/mail is simply inaccessable by
the client unless they unmount /Users/joe/mail->/home/joe/mail and then
access /home/joe/mail.

> If it's not empty and the second on were to succeed,
> what files are visible there (from nfs-one, or nfs-two)?

nfs-two,  mounts are not transparent.

> If this actualy does work reliably and is stable, 

It should be stable.  Accessing a mbox type mailbox from multiple hosts
IS NOT!  But the filesystem is stable.

> then there are a couple 
> of diffferent ways to organizre stuff, and this can be very flexible without
> creating confusing messes, wof which the above is a VERY SIMPLE example. If
> it does not work or is unstable and buggy,

Well, it isn't buggy on what can be considered recent kernels running
NFSv3 and a good lock implementation. 2.2.x's version of NFSv2 and
associated locking......well, I wouldn't want to fly over enemy
territory in that thing.