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Getting started

CSC uses a batch job system to schedule and execute computing tasks on our supercomputers.

Typically, a batch job first loads a software environment using the module system and then executes a program to do some computing. Importantly, a batch job is also required to specify the resources (runtime, memory, cores, etc.) needed for the execution of the job.

This section introduces the basics of creating and submitting batch jobs using the SLURM batch job system at CSC.

Note that also interactive tasks (other than compiling, moving data and light pre- and post-processing) are to be done via the batch job system. See Usage policy for details.

Key concepts of the CSC batch job system

  1. Jobs do not run instantly, but are put in a queue.
    • The jobs are executed when there are resources available. The starting time also depends on your job's priority score.
    • The priority score of a job exists to ensure fair sharing of computational resources between all the users of the cluster. Running a lot of jobs will decrease the initial priority score of your jobs. The priority score will then increase gradually as your job waits in the queue.
  2. The starting time of a job cannot be predicted accurately.
    • It depends heavily on the actual runtimes of all other users' jobs and whether new jobs are submitted. See FAQ.
  3. Computational resources (e.g. runtime, memory, number of cores) are requested explicitly.
    • If the reserved time or memory limits are exceeded, the job will be terminated automatically!

To get started with running your application on CSC supercomputers:

  1. Creating a batch job script for Puhti
  2. Creating a batch job script for Mahti
  3. Submit a batch job
  4. Available batch job partitions
  5. Performance checklist

If you are already familiar with SLURM, check out our example batch job scripts for Puhti or example batch job scripts for Mahti.

Getting started with LUMI

Please see the LUMI documentation for how to get started with running jobs on the LUMI supercomputer. LUMI also uses the SLURM batch queue system, so the differences between running on CSC supercomputers and LUMI are minor.

Last update: July 18, 2024