[slurm-users] Set all Fairshares manually

Michael Müller Michael.Mueller12 at tu-dresden.de
Thu Mar 4 12:50:32 UTC 2021

Dear Slurm users,

we are running a cluster that has a flat account structure. All accounts
have a monthly limit that can only change on the 1st of a month. Users
assigned to the very same account shall not compete against each other
(created with fairshare=parent) and their fairshare shall be calculated
only regarding consumption in the current month. We are using the
multifactor priority plugin.

I tried to set:


What I expected:
If an account used 50% of its budget, its fairshare value will be 0.75,
independently of the day of the month.

What happens:
The raw_usage does not get normalised against the max-cluster raw_usage
of the current month. It does not even get normalised against the
max-cluster raw_usage of the time passed in the current month, but only
against the raw usage of all projects. This will also lead to
fluctuating values if the cluster is not used near full capacity.

This leads to projects that have used 50% of their budget on the 3th day
of the month suddenly seeing fairshare values below 0.005. Since I do
not see any option to get the fairshare calculation the way I want it to
work, I am now trying to manually set the fairshare values. However, I
can't find an option to turn of the internal fairshare calculation.

Please help me with the Slurm configuration so that the fairshare values
are not automatically recalculated and the manual set values remain.

Would it be enough to set PriorityCalcPeriod to an extremely high value
or 0?

I am aware that the manually calculated and propagated fairshare values
will not be updated as often and am fine with that.
I am also aware that balancing might not be as smooth with this method,
but we need transparent and understandable fairshare values.

With kind regards
Michael Müller

Michael Müller
Application Developer / Administrator

Department of System and Service Design (SDE)
Center of Information Services and High Performance Computing (ZIH)
Dresden University of Technology
01069 Dresden

phone: (0351)463-35261
www:   www.tu-dresden.de/zih

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