[slurm-users] slurm node weights

[Brian Andrus]

The intention there is to pack jobs on the smallest node that can handle 
the job.

This way jobs that only need 1 cpu don't take it from a 64-core node 
unless it has to, leaving that one available for that 64-core job.


It really boils down to what you want to happen, which will vary with 
each installation.


Brian Andrus


On 9/5/2019 8:48 AM, Douglas Duckworth wrote:
> Hello
>
> We added some newer Epyc nodes, with NVMe scratch, to our cluster and 
> so want jobs to run on these over others.  So we added "Weight=100" 
> /*to the older nodes*/ and left the new ones blank. So indeed, ceteris 
> paribus, srun reveals that the faster nodes will accept jobs over 
> older ones.
>
> We have the desired outcome though I am a bit confused by two 
> statements in the manpage <https://slurm.schedmd.com/slurm.conf.html> 
> that seem to be contradictory:
>
> "All things being equal, jobs will be allocated the nodes with the 
> lowest weight which satisfies their requirements."
>
> "...larger weights should be assigned to nodes with more processors, 
> memory, disk space, higher processor speed, etc."
>
> 100 is larger than 1 and we do see jobs preferring the new nodes which 
> have the default weight of 1.  Yet we're also told to assign larger 
> weights to faster nodes?
>
> Thanks!
> Doug
>
> -- 
> Thanks,
>
> Douglas Duckworth, MSc, LFCS
> HPC System Administrator
> Scientific Computing Unit <https://scu.med.cornell.edu/>
> Weill Cornell Medicine"
> E: doug at med.cornell.edu
> O: 212-746-6305
> F: 212-746-8690
>
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