[slurm-users] [External] Defining a default --nodes=1

[Fulcomer, Samuel]

"-N 1" restricts a job to a single node.

We've continued to have issues with this. Historically we've had a single
partition with multiple generations of nodes segregated for
multinode scheduling via topology.conf. "Use -N 1" (unless you really know
what you're doing) only goes so far.

There are a few other things that we may address in a submission plugin,
and this will be added.

As previously mentioned, the other approach is to have a partition limited
to single-node scheduling (as the default partition), and advise users who
really know how to do multi-node process management (MPI or other) to use
an overlapping partition.



On Fri, May 8, 2020 at 4:10 PM Michael Robbert <mrobbert at mines.edu> wrote:

> Manuel,
>
> You may want to instruct your users to use ‘-c’ or ‘—cpus-per-task’ to
> define the number of cpus that they need. Please correct me if I’m wrong,
> but I believe that will restrict the jobs to a singe node whereas ‘-n’ or
> ‘—ntasks’ is really for multi process jobs which can be spread amongst
> multiple nodes.
>
>
>
> Mike
>
>
>
> *From: *slurm-users <slurm-users-bounces at lists.schedmd.com> on behalf of
> "Holtgrewe, Manuel" <manuel.holtgrewe at bihealth.de>
> *Reply-To: *Slurm User Community List <slurm-users at lists.schedmd.com>
> *Date: *Friday, May 8, 2020 at 03:28
> *To: *"slurm-users at lists.schedmd.com" <slurm-users at lists.schedmd.com>
> *Subject: *[External] [slurm-users] Defining a default --nodes=1
>
>
>
> *CAUTION:* This email originated from outside of the Colorado School of
> Mines organization. Do not click on links or open attachments unless you
> recognize the sender and know the content is safe.
>
>
>
> Dear all,
>
>
>
> we're running a cluster where the large majority of jobs will use
> multi-threading and no message passing. Sometimes CPU>1 jobs are scheduled
> to run on more than one node (which would be fine for MPI jobs of course...)
>
>
>
> Is it possible to automatically set "--nodes=1" for all jobs outside of
> the "mpi" partition (that we setup for message passing jobs)?
>
>
>
> Thank you,
>
> Manuel
>
>
>
> --
> Dr. Manuel Holtgrewe, Dipl.-Inform.
> Bioinformatician
> Core Unit Bioinformatics – CUBI
> Berlin Institute of Health / Max Delbrück Center for Molecular Medicine in
> the Helmholtz Association / Charité – Universitätsmedizin Berlin
>
> Visiting Address: Invalidenstr. 80, 3rd Floor, Room 03 028, 10117 Berlin
> Postal Address: Chariteplatz 1, 10117 Berlin
>
> E-Mail: manuel.holtgrewe at bihealth.de
> Phone: +49 30 450 543 607
> Fax: +49 30 450 7 543 901
> Web: cubi.bihealth.org  www.bihealth.org  www.mdc-berlin.de
> www.charite.de
>
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