ARCHIVED: About Moab

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Moab is a job scheduling and management system for use on clusters, supercomputers, and grids. Highly optimized and configurable, Moab can support a large array of scheduling and fairness policies, dynamic priorities, and extensive reservations. Patented by Adaptive Computing, Inc., Moab is widely used to optimize the manageability and efficiency of systems ranging in complexity from clusters of a few processors to multi-teraFLOPS supercomputers.

Following are some common, useful Moab commands:

Moab command Function
showq Display the jobs in the Moab job queue.
(Jobs may be in a number of states; "running" and "idle" are the most common.)
checkjob jobid Check the status of a job (jobid). For verbose mode, add -v (for example, checkjob -v jobid).
showstart jobid Show an estimate of when your job (jobid) might start.
mdiag -f Show fairshare information.
checknode node_name Check the status of a node (node_name).
showres Show current reservations.
showbf Show intervals and node counts presently available for backfill jobs.
In older versions of Moab, use diagnose -f instead of mdiag -f to view fairshare information.

For more Moab commands and their descriptions, see the Adaptive Computing Scheduler Commands page.

Fairshare scheduling

Fairshare scheduling allows historical resource usage to affect job priority decisions. Administrators can set target usage goals for each user, group, class, or service group. Moab tracks class usage and gives priority to other job classes when one job class exceeds its usage goals.

To display Moab's fairshare scheduling usage table, use the mdiag -f command.

Estimate when your job will start

Moab uses fairshare tables to determine which job gets assigned to the next open processors. To view the states of submitted jobs, use the showq command.

To view a list of existing reservations, use the showres command.

To view the estimated start time of a job (jobid), use:

showstart jobid

If a job already has a node or nodes reserved, showstart will display the reservation start time. In all other cases, showstart will display the earliest possible start time, assuming the job in question has the highest priority. In most cases, your job will not have the highest priority, so showstart will provide only an estimate of its start time.

Display jobs eligible for scheduling

To view the priority of all jobs eligible for scheduling, use:

showq -i

This is document avmu in the Knowledge Base.
Last modified on 2021-04-11 07:02:11.