Each DAS-2 cluster consists of a file/compile server and a number of
compute nodes.
The file/compile server 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-2 must be used in the following way:
Program development (editing, compiling) is done on the
file/compile servers.
Program execution MUST be done on the compute nodes,
NEVER on a file/compile server.
The file/compile servers are usually heavily loaded just carrying
out the tasks they are intended for.
User programs that run on a file/compile server harm all other
users of that DAS-2 cluster!
This rule also holds for sequential runs of parallel
programs.
Running of jobs on the worker nodes MUST be done via
the DAS-2 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 DAS-1 scheduler
prun
has also been ported to the DAS-2 scheduler. For many users
this will be the most convenient way to start jobs.
The default run time for jobs scheduled on DAS-2 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-2, preferably
use the cluster at your own site, unless it is overloaded
and another one happens to be free.
DAS-2 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-2 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!
