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Subject: Re: [OMPI users] Problem with running openMPI program
From: Ankush Kaul (ankush.rkaul_at_[hidden])
Date: 2009-04-06 12:16:01


I am not able to check if NFS export/mount of /tmp is working,
when i give the command *ssh 192.168.45.65 192.168.67.18* i get the error :
bash: 192.168.67.18: command not found

let me explain what i understood using an example.

First, i make a folder '/work directory' on my master node.

Then i mount this directory on a folder named '/work directory/mnt' on the
slave node

is this correct?

also how and where (is it on the master node) do i give the list of hosts?
and by hosts you mean the compute nodes.

Plez bear with me as this is the first time i am doin a project on Linux
clustering.

On Mon, Apr 6, 2009 at 9:27 PM, Gus Correa <gus_at_[hidden]> wrote:

> Hi Ankush
>
> If I remember right,
> mpirun will put you on your home directory, not on /tmp,
> when it starts your ssh session.
> To run on /tmp (or on /mnt/nfs)
> you may need to use "-path" option.
>
> Likewise, you may want to give mpirun a list of hosts (-host option)
> or a hostfile (-hostfile option), to specify where you want the
> program to run.
>
> Do
> "/full/path/to/openmpi/mpriun -help"
> for details.
>
> Make sure your NFS export/mount of /tmp is working,
> say, by doing:
>
> ssh slave_node 'hostname; ls /tmp; ls /mnt/nfs'
>
> or similar, and see if your program "pi" is really there (and where).
>
> Actually, it may be confusing to export /tmp, as it is part
> of the basic Linux directory tree,
> which is the reason why you mounted it on /mnt/nfs.
> You may want to choose to export/mount
> a directory that is not so generic as /tmp,
> so that you can use a consistent name on both computers.
> For instance, you can create a /my_export or /work directory
> (or whatever name you prefer) on the master node,
> export it to the slave node, mount it on the slave node
> with the same name/mountpoint, and use it for your MPI work.
>
> I hope this helps.
> Gus Correa
> ---------------------------------------------------------------------
> Gustavo Correa
> Lamont-Doherty Earth Observatory - Columbia University
> Palisades, NY, 10964-8000 - USA
> ---------------------------------------------------------------------
>
> Ankush Kaul wrote:
>
>> Thank you sir,
>> one more thing i am confused about, suppose i have 2 run a 'pi' program
>> using open mpi, where do i place the program?
>>
>> currently i have placed it in /tmp folder on de master node. this /tmp
>> folder is mounted on /mnt/nfs of the compute node.
>>
>> i run de progam from the tmp folder on de master node, is this correct?
>>
>> i m a newbie n really need some help, thanks in advance
>>
>> On Mon, Apr 6, 2009 at 8:43 PM, John Hearns <hearnsj_at_[hidden]<mailto:
>> hearnsj_at_[hidden]>> wrote:
>>
>> 2009/4/6 Ankush Kaul <ankush.rkaul_at_[hidden]
>> <mailto:ankush.rkaul_at_[hidden]>>:
>> >> Also how do i come to know that the program is using resources
>> of both the
>> > nodes?
>>
>> Log into the second node before you start the program.
>> Run 'top'
>> Seriously - top is a very, very useful utility.
>> _______________________________________________
>> users mailing list
>> users_at_[hidden] <mailto:users_at_[hidden]>
>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>>
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