Fair share

A share refers to a certain fraction of the available time on the cluster. Suppose there are 125 "job slots" on the cluster (meaning up to 125 jobs can run concurrently); if your virtual organization has a 6% share on the cluster, then your VO has been allocated 7.5 job slots. It is important to remember that the main factor in the fair share is time used -- on a given day suppose your VO runs 270 jobs, each lasting for 17 minutes. This is a total of 17 * 60 * 270 = 275,400 processor-seconds of computing. Per day the cluster is able to 125 * 86,400 = 10.8 million processor-seconds of computing, hence for this given day your VO has used a share of 2.55% of the cluster. In this case, for that given day, your VO could have used more cycles since 2.55% is less than the 6% share allocated, even though 270 jobs is way above the 7.5 "allocated" job slots and even larger than the 125 "available" job slots -- the total time is what is important.