I've used Paul's `MaxJobs` suggestion in emergencies with success.  +1 vote.

We've encountered RPC timeouts and have been able to tune the 
`sched_max_job_start` (decrease) and `sched_min_interval` (increase) options of 
`SchedulerParameters` to reduce/eliminate timeouts during high job flux.  
Selecting good values required some trial and error.

Good luck!

Sebastian

--

[University of Nevada, Reno]<http://www.unr.edu/>
Sebastian Smith
High-Performance Computing Engineer
Office of Information Technology
1664 North Virginia Street
MS 0291

work-phone: 775-682-5050<tel:7756825050>
email: stsm...@unr.edu<mailto:stsm...@unr.edu>
website: http://rc.unr.edu<http://rc.unr.edu/>

________________________________
From: slurm-users <slurm-users-boun...@lists.schedmd.com> on behalf of Paul 
Edmon <ped...@cfa.harvard.edu>
Sent: Tuesday, September 22, 2020 5:01 PM
To: slurm-users@lists.schedmd.com <slurm-users@lists.schedmd.com>
Subject: Re: [slurm-users] Quickly throttling/limiting a specific user's jobs


I would look at:

MaxJobs=<max jobs>
Maximum number of jobs each user is allowed to run at one time in this 
association. This is overridden if set directly on a user. Default is the 
cluster's limit. To clear a previously set value use the modify command with a 
new value of -1.

Which is Association based.  So you could just modify their account directly 
and set it to something low.

You can also simply put their pending jobs in hold state.  That way they won't 
be considered for scheduling but won't be outright removed.  Setting fairshare 
to 0 has the same effect.

-Paul Edmon-

On 9/22/2020 7:58 PM, Brian Andrus wrote:

Well, I know of no way to 'throttle' running jobs. Once they are out the gate, 
you can't stop them from leaving..

That said, your approach of setting arraytaskthrottle is just what you want for 
any pending jobs.

As a preventative measure, I imagine you could set the default to 1 and then 
change it with a job_submit script.

As far as currently running tasks, well, you have to figure that. You could 
kill/requeue them, but that can break things for the user. If their code 
supports it, they could checkpoint/restart as part of the process.

You can suspend them, but they still sit on the node waiting to be resumed, but 
the node resources may get assigned to other jobs while they wait to resume.

Brian Andrus


On 9/22/2020 2:33 PM, Ransom, Geoffrey M. wrote:

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