The Distributed ASCI Supercomputer 3

DAS-3 Usage Policy


Each DAS-3 cluster consists of a headnode (file/compile server) and a number of compute nodes. The headnode is called fsX (X is 0, 1, 2, 3 or 4 according to the cluster base); the worker nodes are named nodeX[0-9][0-9].

The DAS-3 must be used in the following way:

  • Program development (editing, compiling) is done on the headnodes, i.e., the file/compile servers.

  • Program execution MUST be done on the compute nodes, NEVER on a headnode. The headnodes are usually heavily loaded just carrying out the tasks they are intended for. User programs that run on a headnode harm all other users of that DAS-3 cluster! This rule also holds for sequential runs of parallel programs.

  • Running of jobs on the worker nodes MUST be done via the DAS-3 cluster scheduling system Sun Grid Engine (SGE), which offers sufficient abstraction and flexibility for nearly all needs. A full documentation set is available.

  • The user interface of the original DAS scheduler prun has also been ported to the DAS-3 scheduler. For many users this will be the most convenient way to start jobs on one of the clusters.

  • The default run time for jobs scheduled on DAS-3 is 15 minutes, which is also the maximum during working hours, from 08:00 to 20:00. We do not want people to monopolize the clusters for a longer time, since that makes interactively running short jobs on a large number of nodes practically impossible. Also, to get a reasonable spread of the load on DAS-3, preferably use the cluster at your own site, unless it is overloaded and another one happens to be free.

  • DAS-3 is specifically NOT a cluster for doing production work. It is meant for people doing experimental research on parallel and distributed programming. Only during the night and in the weekend, when DAS-3 is regularly idle, it is allowed to run long jobs. In all other cases, you will first have to ask permission in advance from das-sysadm@cs.vu.nl to make sure you are not causing too much trouble for other users.

NOTE: Users who do not obey these usage rules, risk blocking of their account!


See also: DAS-3 User Accounts and DAS-3 Job Execution.


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