I don't know where the machinefile is ?. I found a command Running with Open MPI mpirun -np 168 -mca btl self,sm,openib –hostfile /home/demo/hostfile-ompi.14 -mca mpi_paffinity_alone 1 ~/WRFV3.2.1/run/wrf.exe. for Dell PowerEdge M610 14-node cluster with Mellanox QDR InfiniBand Switch , but I am still not able to make it run with my system. i have Dell PowerEdge M600 cluster with Infiniband.

Message: 3
Date: Fri, 1 Apr 2011 22:02:59 -0700
From: David Zhang <solarbikedz@gmail.com>
Subject: Re: [OMPI users] WRF run on multiple Nodes
To: Open MPI Users <users@open-mpi.org>
Message-ID: <BANLkTikufhi=8HK-MPoUoCPNCkiqFsPKoQ@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

look into -machinefile

On Fri, Apr 1, 2011 at 8:16 PM, Ahsan Ali <ahsanshah01@gmail.com> wrote:

> Hello,
>
> I want to run WRF on multiple nodes in a linux cluster using openmpi,
> giving the command *mpirun -np 4 ./wrf.exe* just submit it to the single
> node . I don't know how to run it on other nodes as well. Help needed.
>
> Regards,
>
> --
> Syed Ahsan Ali Bokhari
> Electronic Engineer (EE)
>
> Research & Development Division
> Pakistan Meteorological Department H-8/4, Islamabad.
> Phone # off +92518358714
> Cell # +923155145014
>
>
> _______________________________________________