What is a chunk in layman's term

[adarsh]

@HeyHey

So for a single chunk, the largest possible chunk is one node’s full and free resources

Yes, largest possible chunk can be the entire compute node or a portion of the compute nodes resources.

Cluster with 2 compute nodes each with 32 cores and 64GB memory

1. if the user wants to run a scalable application job across 2 nodes but using 8 core and 16 GB memory from each of the compute node, then

-l select=2:ncpus=8:mem=16gb -l place=scatter

-l select=2:ncpus=8:mem=16gb:mpiprocs=8 -l place=scatter (MPI)

The remaining resources of those nodes can be used by other jobs , until all the resources are used up.

FYI: Split chunk statements

Ncpus=1+1:ncpus=24

I’m a little confused as to why: #PBS -l select=1:ncpus=1+1:ncpus=1 doesn’t pull an error up, while: #PBS -l select=1:ncpus=1:ncpus=1 produces the error: “qsub: duplicated resource within a section of a select specification, resource is: ncpus” Can anyone explain it for me?