[slurm-users] More cores than on one node

[Loris Bennett]

>Nadav Toledo <nadavtoledo at cs.technion.ac.il> writes:
>
>>  Nadav Toledo <nadavtoledo at cs.technion.ac.il> writes:
>>
>>  Hey everyone,
>>
>> We've just setup a slurm cluster with few nodes each has 16 cores.
>> Is it possible to submit a job for 17cores or more?
>> If not, is there a workaround?
>>
>> Thanks in advance, Nadav
>>
>>
>> It should be possible.  Have you tried?  If so, do you get an error?
>>
>>
>
> srun -c17 --pty bash
> srun: error: CPU count per node can not be satisfied
> srun: error: Unable to allocate resources: Requested node configuration is not available

The option -c is the short form of --cpus-per-task, which really means
"cores per process".  As you only have 16 cores per node, you can't run
a single process on 17 cores.

You probably want 

  srun --ntasks=17 --pty bash

I'd suggest you use the long forms of the options until you get more
familiar with Slurm (although even that can still be confusing,
cf. core/cpu, task/process).

Cheers,

Loris

-- 
Dr. Loris Bennett (Mr.)
ZEDAT, Freie Universität Berlin         Email loris.bennett at fu-berlin.de