Launching Jobs

Launch an Interactive Job

Saguaro is a massively parallel cluster – a collection of many small compute nodes that are interconnected with a high-speed, low-latency network fabric. There are a small number of Internet facing head (or login) nodes that are shared by all users accessing the system. If you need to perform any compute intensive tasks, you need to request access to one or more of the compute nodes by enqueuing a job. The simplest case for this is an interactive job that gives you direct control over the compute node(s). In order to start an interactive job, just login to Saguaro and then use the ‘qsub’ command.

saguaro1:~/ > qsub -I

(note that is a capital ‘i’ for ‘interactive’, not a lower case ‘L’) This will give you something like the following:

qsub: waiting for job 4213873.moab.local to start

qsub: job 4213873.moab.local ready

 

s50-10:~/ >

You now have an interactive shell on one of the compute nodes, in this case ‘s50-10’.

Loading Modules

Software packages and libraries on Saguaro are packaged into ‘modules’. You can see a current listing of the set of available modules at our software page or from the command line.

[saguaro1:~]$ module avail

To load a specific module from that list:

[saguaro1:~]$ module load openmpi/1.4.3-intel

This will load the Intel compiler suite with the OpenMPI version 1.4.3 library. (Note that when you are reading this, that version is probably out of date; be sure to check the available modules). Whenever you open a new shell by connecting to Saguaro or using a job script, you will start with a clean slate so be sure to load whatever modules you require before continuing to avoid frustration.