Scheduler

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The queueing system used at SciNet is based around Cluster Resources Moab Workload Manager. Moab is used on both the GPC and TCS however Torque is used as the backend resource manager on the GPC and IBM's LoadLeveler is used on the TCS.

This page outlines some of the most common Moab commands with full documentation available from Moab here.

Queue Info

To see all jobs queued on a system use

showq

Three sections are shown; running, idle, and blocked. Idle jobs are commonly referred to as queued jobs as they meet all the requirements, however they are waiting for available resources. Blocked jobs are either caused by improper resource requests or more commonly by exceeding a user or groups allowable resources. For example if you are allowed to submit 10 jobs and you submit 20, the first 10 jobs will be submitted properly and either run right away or be queued, however the other 10 jobs will be blocked and the jobs won't be submitted to the queue until one of the first 10 finishes.

If showq is returning output slowly, you can query cached info using

showq --noblock

Available Resources

To show how many total nodes are currently free use or will be free including reservations use the show back fill command

showbf -A 

To show how many infiniband nodes are free use

showbf -f ib

For example

$ showbf -A
Partition     Tasks  Nodes      Duration   StartOffset       StartDate
---------     -----  -----  ------------  ------------  --------------
ALL           14728   1839       7:36:23      00:00:00  00:23:37_09/24
ALL             256     30      INFINITY      00:00:00  00:23:37_09/24

shows that for jobs under 7:36:23 you can use 1839 nodes, but if you submit a job over that time only 30 will be available. In this case this is due to a large reservation made my SciNet staff, but from a users point of view, showbf tells you very simply what is available and at what time point.

In this case, a user may wish to set #PBS -l walltime=7:30:00 in their script, or add -l walltime=7:30:00 to their qsub command in order to ensure that the jobs backfill the reserved nodes.

Job Submission

Interactive

On the GPC an interactive queue session can be requested using the following

qsub -l nodes=2:ppn=8,walltime=1:00:00 -I

Non-interactive (Batch)

For a non-interactive job submission you require a submission script formatted for the appropriate resource manger. Examples are provided for the GPC and TCS.

Job Status

checkjob jobid

Cancel a Job

canceljob jobid

User Stats

Show current usage stats for a $USER

showstats -u $USER

Reservations

showres

Standard users can only see their reservations not other users or system ones. To determine what is available a user can use"showbf", it shows what resources are available and at what time level, taking into account running jobs and all the reservations.