When slurm is considering jobs to schedule including job arrays out of all 
pending jobs, does slurm consider only the job array individually, or does it 
consider the child jobs behind them?  I’m curious as I’ve to date limited the 
size of job arrays to 4000 to be proportional with our max queue limit of 
13,000.  I’ve done this in order to keep the job depth at a reasonable size for 
efficient slurm scheduling and backfilling (maybe not needed!).  But to date, 
I, and the folks utilizing our cluster have been pleased with the scheduling 
being done, and speed on our cluster; I don’t want to change that! ☺

I have a researcher now wanting to process 100K+ inputs with slurm arrays, and 
my 4000 limit is becoming a burden where we’ve been looking into ways to work 
around it. I’ve started rethinking my original 4000 number and am now wondering 
if it’s necessary to keep the array size so low.

A man on slurm.conf gives the impression that if I change the slurm array size, 
the max queue size has to be augmented to a higher value.  This would indicate 
to me that this would in fact impact the scheduling significantly as now for 
backfill, there has to be potentially many more jobs tested before starting 

I’d like to get some feedback on this please from other sites and the 
developers if possible.  Thank you! 


Christopher Coffey
High-Performance Computing
Northern Arizona University

Reply via email to