Lustre File Systems

Many supercomputers use the Lustre file system, which has multiple Object Storage Targets (OSTs). Using more of these improves output speed for the large files produced by Vorpal in large-scale computing. The number to be used is set by a stripe command, such as

:

lfs setstripe –count C .

which sets the number of OSTs to C in the current directory. As noted at https://www.nersc.gov/users/storage-and-file-systems/i-o-resources-for-scientific-applications/optimizing-io-performance-for-lustre/, one should set C according to

PBS/Torque/OpenPBS

Here is an example of a basic shell script for a PBS-based system.

#PBS -N vaclaunch
#PBS -l nodes=2:ppn=2
export VSIM_DIR=$HOME/VSim-10.0
source $VSIM_DIR/VSimComposer.sh
cd /directory/containing/your/input/file
mpiexec -np 4 vorpal -i vaclaunch.pre -n 250 -d 50

The -l commands relate to the resource requirements of the job. This file explicitly specified the number of cores per node, and number of nodes, so we have a total of four MPI ranks on which to execute the job, which is mirrored in the mpiexec -np argument.

If the contents of the above file are in vaclaunch.pbs, then the job would commonly be submitted by

qsub vaclaunch.pbs

although some MOAB based systems might use msub.

Sun Grid Engine (SGE)

Here is another example, this time for a SGE (Sun Grid Engine) job.

#$ -cwd -V
#$ -l h_rt=0:10:00
#$ -l np=16
#$ -N magnetron2D
export VSIM_DIR=$HOME/VSim-10.0
source $VSIM_DIR/VSimComposer.sh
mpiexec -np 16 vorpal -i magnetron2D.pre

This time the -cwd -V tells the queue system to use the current working directory for the job, and to import the current environment and make this avialable for the script.

In this case, the queue system calculates the configuration based on the choice of 16 cores. On this cluster the -l commands is also used to specify the run duration, which, in this example, is set to 10 minutes.

If the contents of the above file are in magnetron2D.qsub, then the job would commonly be submitted by

qsub magnetron2D.pbs

Platform LSF

Here is a third example, for the Platform LSF system:

#BSUB -o EBDP-VSim10.0.out
#BSUB -e EBDP-VSim10.0.err
#BSUB -R "span[ptile=16]"
#BSUB -n 32
#BSUB -J testVSim10.0
#BSUB -W 45
cd $HOME/electronBeamDrivenPlasma
export VSIM_DIR=$HOME/VSim-10.0
source $VSIM_DIR/VSimComposer.sh

export MYJOB=electronBeamDrivenPlasma.pre

mpiexec -np 32 vorpal -i ${MYJOB}

With this submission system and job scheduler, -W is used to denote the wall time for the job in minutes. The name is passed by -J.

Sometimes one must reference a specific project for accounting purposes in the job submission file. For this you may use the -A option.

If the above commands are in the file, electronBeamDrivenPlasma.lsf, then the job is commonly submitted by

bsub < electronBeamDrivenPlasma.lsf

Slurm

Here is an example from a Cray system with a custom Vorpal build running from a directory /project/nnnnn/gnu-5.2.40.

#!/bin/bash
#SBATCH --account=nnnnn
#SBATCH --job-name=lpa
#SBATCH --output=lpa.out
#SBATCH --error=lpa.err
#SBATCH --nodes=2
#SBATCH --time=00:05:00
srun --ntasks=32 --hint=nomultithread --ntasks-per-node=16 /project/nnnnn/gnu-5.2.40/vorpal-exported/bin/vorpal -i laserPlasmaAccel.pre -n 100 -d 20

If the file containing the above is named, laserPlasmaAccel.slm, then this job is submitted with

sbatch laserPlasmaAccel.slm

You can check on your job with

squeue -u $USER

and you can stop the job with

scancel JOBID

where JOBID is the job id returned by squeue.