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

[Robert G. Brown]

On Sun, 11 Jan 2004 18:59:50 -0500, Bruce Smith wrote:

>> >As a tip, it's possible (and sometimes less confusing) to mount the
>> >remote directory on a local directory of the same name....
>> Thanks.  Haven't answered the question.
>Because there was no question ask in the original email.
>You ask for a ranking, but ask no question.
But you didn't even give a ranking, you gave "N/A" :)

>Your two mount commands seemed to be unrelated, so I must be missing
>something.  I don't have a clue how to rank such a thing.
>Here, rank this command for me:  ls
11 ! :)

Consider:
mount nfs-one:/Users /home
mount nfs-two:/shared/mail/joe /home/joe/mail

OK, they're related since there's a /Users/joe on nfs-one (I know, I 
didn't say that, but I am now), which of course becomes /home/joe on
the local machine.

Now I want make something else, frm another NFS server, visible to 
poor joe when he logs in. The second mount looks like [??] it does
this, but I understand that these sorts of things CAN (maybe) lead
to problems. Organizationally, it looks right, but if this sort of thing
is not handled with great deftness by the server (or the client), it
could also be a real plane crash.

I understand, for example, that not only isd this unnesseary, but it 
apparently can lead to real problems:

mount nfs-one:/a  /b
mount nfs-one:/a/b /b/c

In this example, we're failing to recognize that it is not nessesary,
since /a/b on nfs-one is already available as /b/b on the local machine.
Moreover, there's lots of funny problems here... /b/d and /b/c/d n the 
local machine (after both mounts) would refer to THE SAME directory on
nfs-one. While this is something that can be resolved cleanly, is it?
I wouldn't want to creat such a configuration, and I'd rank anyone VERY
LOW on my own food chain if I saw it.

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

If this actualy does work reliably and 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, then file organization must be 
much more rigorous, and some schemes have to be carefully checked and
maybe discarded like last weeks' milk before use.

							Regards,
							---> RGB <---