Hi Belaid Moa
Belaid MOA wrote:
Thank you very very much Gus. Does this mean that OpenMPI does not copy
the executable from the master node to the worker nodes?
Not that I know.
Making the executable available on the nodes, and any
input files the program may need, is the user's responsibility,
not of mpiexec.
On the other hand,
Torque/PBS has a "stage_in/stage_out" feature that is supposed to
copy files over to the nodes, if you want to give it a shot.
See "man qsub" and look into the (numerous) "-W" option under
the "stage[in,out]=file_list" sub-options.
This is a relic from the old days where everything had to be on
local disks on the nodes, and NFS ran over Ethernet 10/100,
but it is still used by people that
run MPI programs with heavy I/O, to avoid pounding on NFS or
even on parallel file systems.
I tried the stage_in/out feature a loooong time ago,
(old PBS before Torque), but it had issues.
It probably works now with the newer/better
versions of Torque.
However, the easy way to get this right is just to use an NFS mounted
directory.
If that's case, I will go ahead and NFS mount my working directory.
This would make your life much easier.
My $0.02.
Gus Correa
---------------------------------------------------------------------
Gustavo Correa
Lamont-Doherty Earth Observatory - Columbia University
Palisades, NY, 10964-8000 - USA
---------------------------------------------------------------------
~Belaid.
> Date: Tue, 1 Dec 2009 13:50:57 -0500
> From: g...@ldeo.columbia.edu
> To: us...@open-mpi.org
> Subject: Re: [OMPI users] Elementary question on openMPI application
location when using PBS submission
>
> Hi Belaid MOA
>
> See this FAQ:
>
http://www.open-mpi.org/faq/?category=running#do-i-need-a-common-filesystem
> http://www.open-mpi.org/faq/?category=building#where-to-install
> http://www.open-mpi.org/faq/?category=tm#tm-obtain-host
>
> Your executable needs to be on a directory that is accessible
> by all nodes in your node pool.
> An easy way to achieve this is to put it in a directory that
> is NFS mounted on all nodes, and launch your pbs script from there.
>
> A less convenient alternative, if no NFS directory is available,
> is to copy the executable over to the nodes.
>
> I also find it easier to write a PBS script instead of putting
> all the PBS directives in the command line.
> In this case you can put the lines below in your PBS script,
> to ensure all nodes will be on your work directory (cd $PBS_O_WORKDIR):
>
> ########
>
> #PBS ... (PBS directives)
> ...
> cd $PBS_O_WORKDIR
> mpiexec -n ....
>
> ########
>
> IIRR, by default Torque/PBS puts you in your home directory on
> the nodes, which may or may not be the location of your executable.
>
> I hope this helps,
> Gus Correa
> ---------------------------------------------------------------------
> Gustavo Correa
> Lamont-Doherty Earth Observatory - Columbia University
> Palisades, NY, 10964-8000 - USA
> ---------------------------------------------------------------------
>
> Belaid MOA wrote:
> > Hello everyone,
> > I am new to this list and I have a very elementary question:
suppose we
> > have three machines, HN (Head Node hosting the pbs server), WN1 (A
> > worker node) and WN (another worker node). The PBS nodefile has WN1
and
> > WN2 in it (DOES NOT HAVE HN).
> > My openMPI program (hello) and PBS script(my_script.sh) reside on the
> > HN. When I submit my PBS script using qsub -l nodes=2 my_script.sh, I
> > get the following error:
> >
> >
--------------------------------------------------------------------------
> > mpirun was unable to launch the specified application as it could not
> > find an executable:
> >
> > Executable: hello
> > Node: WN2
> >
> > while attempting to start process rank 0.
> >
--------------------------------------------------------------------------
> >
> > How come my hello program is not copied automatically to the worker
> > nodes? This leads to my elementary question:
> > where the application should be when using a PBS submission?
> >
> > Note that when I run mpirun from HN with machinefile containing WN1
and
> > WN2, I get the right output.
> >
> > Any help on this is very appreciated.
> >
> > ~Belaid.
> >
> >
> >
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