Biowulf High Performance Computing at the NIH
Online class: Introduction to Biowulf

Thought Exercises: Walltimes

What's the disadvantage of submitting jobs with long walltimes if they are not needed?


The batch system will take longer to schedule your jobs. In general, ask for as few resources as possible.

What's the problem if a single swarm subjob takes 1 hr, and you want to submit the swarm with a bundle factor of 500?


500 * 1 hr = 500 hours = 20 days. This is longer than the max walltime of 10 days, and your swarm command will give an error.

You will need to reduce the bundle factor to a max of 240 (exactly 10 days) or a bit less.