[Beowulf] mpirun and batch systems

[Reuti]

> I have a question about how various batch systems run MPI jobs.
> 
> Say I have a head node and 16 compute nodes. I submit a job
> that requires 8 nodes, and the batch system allocates me
> nodes 4,5,6,7,8,9,10,11. 
> 
> Where does my 'mpirun' get executed from? On the head node? Or on
> node 4? 

For SGE, but I think for others also, on one of the nodes e.g. node 4 when the 
job is scheduled. I always try to speak to my users of "master node" of the 
cluster and "head node" of a MPI job to avoid confusion. - Reuti