I've started playing with powersave and have a question about SuspendExcNodes. The documentation at https://slurm.schedmd.com/power_save.html says
For example nid[10-20]:4 will prevent 4 usable nodes (i.e IDLE and not DOWN, DRAINING or already powered down) in the set nid[10-20] from being powered down. I initially interpreted that as "Slurm will try to keep 4 nodes idle on as much as possible", which would have reduced the wait time for new jobs targeting those nodes. Instead, it appears to mean "Slurm will not shut off the last 4 nodes which are idle in that partition, however it will not turn on nodes which it shut off earlier unless jobs are scheduled on them" Most notably if the 4 idle nodes will be allocated to other jobs (and so they are no idle anymore) slurm does not turn on any nodes which have been shut off earlier, so it's possible (and depending on workloads perhaps even common) to have no idle nodes on regardless of the SuspendExcNode settings. Is that how it works, or do I have anything else in my setting which is causing this unexpected-to-me behavior? I think I can live with it, but IMHO it would have been better if slurm attempted to turn on nodes preemptively trying to match the requested SuspendExcNodes, rather than waiting for job submissions. Thanks and Happy Thanksgiving to people in the USA
