From: pasq@cup.hp.com (Mark Di Pasquale)
Subject: Re: Mail in 710 cluster with NFS fails
Date: Sat, 7 Nov 1992 00:10:08 GMT
Organization: Hewlett-Packard
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enisaxg@state.systems.sa.gov.au wrote:
: Problem with Mail under a common NFS mounted /usr/mail.
: ...
:
: We have no problem running any mailers between the CDC, SUN, and HP 847.
: We do, however, have 5 HP 710's running as a cluster off of one server.
: 
: On the HP 710 *server*, there is no problem accessing the NFS common maildrop.
: 
: On *clients* of the HP 710, there is no way we can access the NFS common
: maildrop! This appears to be related to the fairly proprietary nature of the
: cluster concept. The errors we get from the clients are:

This may have something to do with "context dependent files".  If the
clients are not gaining access to some resource the server has, it may
be that the "resource" does not have a "context" for the clients.  For
example, on your server system, /etc/inittab is a context-dependent file
(CDF).  If you were to "cd /etc/inittab+" and do an ls(1), you should
see the names of all of your clients, and the server's name (or
something like "localroot", which means "the rootserver").  In this
case, each "name" listed is a unique file, one for each machine in the
cluster.  But the name is important!!  For example, if you have a client
named hptm1 listed in /etc/inittab+, and you were to "mv
/etc/inittab+/hptm1 /tmp", then client hptm1 would no longer be able to
see /etc/inittab:

	hptm1: ls /etc/inittab
        /etc/inittab not found
	hptm1:

Now, if the problem you are experiencing with /usr/mail relates to
context, then you have a CDF file or directory that does not have the
names of the clients listed (or the key-word "remoteroot" which means
"all machines in the cluster that are not the rootserver").

More specifically, when you are accessing the "common mail drop" from
your server, I assume you have a directory/file on the server machine
that "points" to the common drop?  For example, you may have done an NFS
mount from the server system like this:

	CDC:/usr/mail /usr/mail nfs ro,soft 0 0

Check to see if /usr/mail (or some other involved file) is a CDF.  You
can do this by:  "cd /usr; ls -H mail".  If you see mail listed as
"mail+", then change directories into mail+ and list the context(s).

Let's say mail is a CDF.  Then, you may find your server's name or the
keyword "localroot" in there:

	/usr/mail+                 or            /usr/mail+
		\                                        \
		localroot                             server_name

Basically, what would have to be done is to make a context for your
clients.  You may be able to do this (in this example) by:

	ln -s localroot remoteroot

creating:
	
	/usr/mail+
		/\
      remoteroot  localroot

I can't guarantee any of this because I don't know where your CDFs are,
or even if this is a CDF-related problem.  But this may help.

See also:  context(5), getcontext(1), and cdf(4)

--
Regards,
Mark DiPasquale

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