Access and Fair Share

Cluster Access

All ZBIT employees have access to the cluster. To prevent authorization/access problems with long-running compute jobs, cluster home directories are located on a NFS server (not in AFS). For this reason, a separate home directory must be created on the cluster for every new user. Additionally, new users have to be assigned to one of the fair share groups, that are used to share compute time equally among the ZBIT groups (see below). If you are a new user to the cluster, send an email to Jan Schulze to have this arranged for you.

Fair Share

Compute time on the cluster is managed via fair share groups. Fair share groups own different amounts of compute time, according to the following table:

Algorithms in BioinformaticsApplied BioinformaticsIntegrative TranscriptomicsCognitive Systems
29%29%29%13%

Every group has got a certain amount of initial fair share tickets, corresponding to the percentage values listed above. CPU time on the cluster reduces tickets. Halflife (i.e. how fast the system forgets about a group's resource consumption) is set to 5 days.

A compensation factor, that limits the maximum cluster usage, is set to three. This means, that it is not possible for a group, to use more than 75% of the cluster, even if that group has much more tickets than any other group with waiting jobs.

The fair share policy may be "distorted" in the following cases: