15. NFS

Users' space needs to be mounted on all nodes so that MPI-applications can read and write stuff.

15.1. Setup

On the master:

 -- check daemons running:
       -- /etc/init.d/portmap start;
       -- /etc/init.d/nfs start;

 -- export /home to all nodes:
     -- /usr/sbin/exportfs 130.88.149.98:/home
        .
        .
        /usr/sbin/exportfs 130.88.149.121:/home

The former can be achieved on subsequent boots by adding appropriate sym-links to /etc/rc?.d.

The latter is better achieved by using adding

     /home       130.88.149.98(rw)
     .
     .
     /home       130.88.149.121(rw)

    /usr/sbin/exportfs -a

On the slaves:

   -- check portmap and nfs.lock working:
       -- /etc/init.d/portmap status  [start if needed]
       -- /etc/init.d/nfslock status  [start if needed]


   -- if needed :
       -- /sbin/modprobe nfs;

Again, add appropriate sym-links to /etc/rc?.d, e.g.,

    ln -s /etc/init.d/portmap /etc/rc5.d/S13portmap
    ln -s /etc/init.d/portmap /etc/rc3.d/S13portmap

           -- and similar for nfslock, nfs...

Nota Bene on using strace:

    using strace on mount seems to upset it --- causing 
    the mount system call to fail (man 2 mount or man -s 2 mount) 

        mount("130.88.149.97:/home", "/mnt/test", "nfs", \
                         0xc0ed0000, 0x80598e0) = -1 EINVAL (Invalid argument)

    when not having the strace it works... (oh fuck, oh fuck, oh fuck...)

15.2. Use!

All slaves mount /home/simonh/_lammpi, say, where all MPI-related code lives (is developed and runs).