Hi George,
George Leaver via slurm-users slurm-users@lists.schedmd.com writes:
Hi Loris,
Doesn't splitting up your jobs over two partitions mean that either one of the two partitions could be full, while the other has idle nodes?
Yes, potentially, and we may move away from our current config at some point (it's a bit of a hangover from an SGE cluster.) Hasn't really been an issue at the moment.
Do you find fragmentation a problem? Or do you just let the bf scheduler handle that (assuming jobs have a realistic wallclock request?)
Well, not with essentially only one partition we don't have fragmentation related to that. We did used to have multiple partitions for different run-times, we did have fragmentation. However, I couldn't see any advantage in that setup, so we moved to one partition and various QOS to handle say test or debug jobs. However, users do still sometimes add potentially arbitrary conditions to their jobs script, such as the number of nodes for MPI jobs. Whereas in principal it may be a good idea to reduce the MPI-overhead by reducing the number of nodes, in practice any such advantage may well be cancelled out or exceeded by the extra time the job is going to have to wait for those specific resources.
Backfill works fairly well for us, although indeed not without a little badgering of users to get them to specify appropriate run-times.
But for now, would be handy if users didn't need to adjust their jobscripts (or we didn't need to write a submit script.)
If you ditch one of the partitions, you could always use a job submit plug-in to replace the invalid partition specified by the job by the remaining partition.
Cheers,
Loris
Regards, George
-- George Leaver Research Infrastructure, IT Services, University of Manchester http://ri.itservices.manchester.ac.uk%C2%A0%7C%C2%A0@UoM_eResearch
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