Fram queue system adjustment

As part of the ongoing work of tuning and improving the queue system on Fram for best resource usage and user experience, we recently upgraded Slurm to version 18.08.

This has enabled us to replace the limit of how many jobs per user the system will try to backfill with a more flexible setting.

Jobs are started and backfilled in priority order, and the priority of jobs increase with time as they are pending. With the new setting, only a fixed number of each user’s jobs within a project will increase in priority. The number is currently 10, but will probably be adjusted over time. This setting will make it easier for all users and projects to get jobs started when one user has submitted very many jobs over a short time, while at the same time not preventing jobs from starting when there are free resources.

Note that the setting is per user and project, so if more than one user submit jobs in the same project, each of them will get 10 jobs with priority increasing, and similarly, if one user submits jobs to several projects, the user will get 10 jobs with priority increasing in each project.

The setting is documented here.