[Beowulf] mpirun and batch systems

[Reuti]

Quoting daniel.kidger at quadrics.com:

Hi,

> Erik,
> > 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? 
> 
> This can depend upon the batch system and how it is configured. What is
> common is for the 'first' (not necessarily the lowest numbered) of the list
> of nodes assigned to a job is the one where the batch scripts executes.
>   The most common alternative is that batch script gets executed on what is
> classed as a 'login node'. 

what's your definition of a "login node"? We have one "login node" where the 
users can "log in", prepare their scripts and input files, one file 
server/queue master (SGE), and many computing nodes. But the submitted batch 
scripts are always executed on the computing nodes only. - Reuti