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In this section I try to explain how your job requests are treated on the
Inside a project, say, HEP 2016/1-4, it doesn't matter who you are, if you're member of the project your requests will be processed FIFO: first in, first out. The first to submit will be the first to have their jobs processed.
As long as the SLURM scheduler can find a slot for the requested resources, it will be possible to run.
But if there are no resources available, all other project members running or queued in front of you will have higher priority –in other words, there is no priority or fair share among members of the same project.
It's like if one were a single person submitting jobs, with many names.
If the cluster is busy, requesting an interactive session may take time and fail. The scheduler will happily allocate resources for a user, but if the user asks for an interactive session with say 6 cores and there is no machine with 6 cores free, the scheduler cannot fulfil the request.
If the user submits a batch job, the scheduler will queue it with the LIFO strategy described above.
So one suggestion from Lunarc is to submit the long, slow jobs first and the fast short ones later, so you give others more and more space as you finish processing the slow ones.
Fairness is enforced among the three projects using the hep partition (HEP 2016/1-3, HEP 2016/1-4, HEP 2016/1-5) that means every project is allocated 1/3 of computing power (core/hours) per month. Once one project exceeds that 1/3, it will be harder for members of that project to get resources when the other projects are running, because there is a debt of computing power towards them.
This happens only when the cluster is being used intensively by all, which is quite rare at the moment of writing.
But if at some point each project is using a considerable amount of computing power, it is for sure that all project members will have to wait in the queue to be allocated. Remember that the allocation is what you ASK for in the sbatch script: once is allocated is yours and others cannot take it.