Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: Re: [OMPI users] More newbie question: LD_LIBRARY_PATH
From: Gus Correa (gus_at_[hidden])
Date: 2011-01-12 21:30:10

Tena Sakai wrote:
> Thank you, Gus.
> I agree with what you say about location of OpenMPI software.
> Indeed, /usr/local is nfs-mounted to all cluster nodes, albeit
> a bit unfortunate name "local." If/when I have a chance to
> Set up machines, I will make local really local to each node.
> Regards,
> Tena Sakai
> tsakai_at_[hidden]
> On 1/12/11 4:20 PM, "Gus Correa" <gus_at_[hidden]> wrote:
>> Tena Sakai wrote:
>>> Hi,
>>> On a FAQ page (
>>> (under 1. What pre-requisites are necessary for running an Open MPI
>>> job?), I see an example
>>> of LD_LIBRARY_PATH environment variable:
>>> LD_LIBRARY_PATH: /opt/openmpi/lib
>>> When I compiled the source, a directory /usr/local/lib/openmpi was
>>> generated (with many
>>> files in it). Given that, do I set D_LIBRARY_PATH to /usr/local/lib or
>>> do I set
>>> it to /usr/local/lib/openmpi?
>>> Thank you.
>>> Tena Sakai
>>> tsakai_at_[hidden]
>> To /usr/local/lib.
>> I would suggest not using the default /usr/local to install OpenMPI,
>> since it tends to be really local to the machine where you built OpenMPI.
>> This will require that you install OpenMPI on all nodes/machines if
>> you want to run programs across a network.
>> Instead, a simpler way to get OpenMPI available to all nodes,
>> although installing only on one of them (say the head node of your
>> cluster) is to do it in a directory that is shared, typically via NFS.
>> To do so, use the --prefix=/my/shared/OpenMPI/directory option of
>> the configure script.
>> There are FAQs about this too.
>> Anyway, it may depend on your environment also, whether it is a cluster
>> with a private subnet (where my suggestion is typically used),
>> a bunch of separate computers on a LAN (where the suggestion won't work
>> unless you have a shared NFS directory), or other.
>> Gus Correa
Hi Tena

Just out of curiosity, this is not really an OpenMPI issue,
and I don't know anything about Rmpi either:

How do you intend to use Rmpi?

Interactively without any resource manager control (Torque,SGI,etc),
as in a standalone PC, although utilizing several hosts via MPI?

Interactively but under resource manager control?
(E.g., Torque has the -I directive for this type of thing,
and I guess other resource managers have similar mechanisms.)

In batch mode, where a full R script runs and eventually exits?
(Which can be with or without a resource manager.)

Maybe it is something else.

Matlab (parallel or not), IDL, etc, just like R[mpi],
bring about the same type of questions for us here.

Gus Correa