Submitting a Job
Once you have a job submission file, you may submit this script to SLURM using the
sbatch command. SLURM will find, or wait for, available resources matching your request and run your job there.
To submit your job to one compute node:
$ sbatch --nodes=1 myjobsubmissionfile
Slurm uses the word 'Account' and the option '-A' to specify different batch queues. To submit your job to a specific queue:
$ sbatch --nodes=1 -A standby myjobsubmissionfile
By default, each job receives 30 minutes of wall time, or clock time. If you know that your job will not need more than a certain amount of time to run, request less than the maximum wall time, as this may allow your job to run sooner. To request the 1 hour and 30 minutes of wall time:
$ sbatch -t 1:30:00 --nodes=1 -A standby myjobsubmissionfile
--nodes value indicates how many compute nodes you would like for your job.
Each compute node in Bell has 128 processor cores.
In some cases, you may want to request multiple nodes. To utilize multiple nodes, you will need to have a program or code that is specifically programmed to use multiple nodes such as with MPI. Simply requesting more nodes will not make your work go faster. Your code must support this ability.
To request 2 compute nodes:
$ sbatch --nodes=2 myjobsubmissionfile
By default, jobs on Bell will share nodes with other jobs.
To submit a job using 1 compute node with 4 tasks, each using the default 1 core and 1 GPU per node:
$ sbatch --nodes=1 --ntasks=4 --gpus-per-node=1 myjobsubmissionfile
If more convenient, you may also specify any command line options to
sbatch from within your job submission file, using a special form of comment:
#!/bin/sh -l # FILENAME: myjobsubmissionfile #SBATCH -A myqueuename #SBATCH --nodes=1 #SBATCH --time=1:30:00 #SBATCH --job-name myjobname # Print the hostname of the compute node on which this job is running. /bin/hostname
If an option is present in both your job submission file and on the command line, the option on the command line will take precedence.
After you submit your job with
SBATCH, it may wait in queue for minutes, hours, or even weeks. How long it takes for a job to start depends on the specific queue, the resources and time requested, and other jobs already waiting in that queue requested as well. It is impossible to say for sure when any given job will start. For best results, request no more resources than your job requires.