Using and Administering

Setting Up a Class for Parallel Jobs

To define the characteristics of parallel jobs run by your installation you should set up a class stanza in the administration file and define a class (in the Class statement in the configuration file) for each task you want to run on a node.

Suppose your installation plans to submit long-running parallel jobs, and you want to define the following characteristics:

• Only certain users can submit these jobs
• Jobs have a 30 hour run time limit
• A job can request a maximum of 60 nodes and 120 total tasks
• Jobs will have a relatively low run priority

The following is a sample class stanza for long-running parallel jobs which takes into account the above characteristics:

  long_parallel: type=class
  wall_clock_limit = 1800
  include_users = jack queen king ace
  priority = 50
  total_tasks = 120
  max_node = 60
  maxjobs = 2

Note the following about this class stanza:

• The wall_clock_limit keyword sets a wall clock limit of 1800 seconds (30 hours) for jobs in this class
• The include_users keyword allows four users to submit jobs in this class
• The priority keyword sets a relative priority of 50 for jobs in this class
• The total_tasks keyword specifies that a user can request up to 120 total tasks for a job in this class
• The max_node keyword specifies that a user can request up to 60 nodes for a job in this class
• The maxjobs keyword specifies that a maximum of two jobs in this class can run simultaneously

Suppose users need to submit job command files containing the following statements:

  node = 30
  tasks_per_node = 4

You must code the Class statement such that at least 30 nodes have four or more long_parallel classes defined. That is, the configuration file for each of these nodes must include the following statement:

  Class = { "long_parallel" "long_parallel" "long_parallel" "long_parallel" }