Monthly Resource Allocation
The monthly accounting and distribution of compute time resources happens at the beginning of each month.
The resource accounting scheme assumes that in the ideal case each project will consume its entire allotted compute time in even portions each month during the duration of the project, usually one year. Since reality is in most cases far from the ideal case, a sliding window of three months is introduced. It allows a one month worth of unused compute time to be carried into the next month, but not further. It is also possible to use in the current month part or all of the next month’s allowance, which usage will then be deducted accordingly at the beginning of the corresponding month. The system allows in extreme cases a total of three months’ worth of compute time to be consumed in a single month.
Once all of the available compute time for a given month has been consumed, further jobs will be dispatched to a low-priority queue and will run only when no other jobs with higher priority are waiting. Further job submission is prevented as soon as one of the following conditions hold:
The monthly quota was exceeded by a factor of 6.
- The total project quota was exceeded by a factor of 2.
One can find a more detailed explanation here.