[slurm-users] Strange output of sshare

[frsc--- via slurm-users]

Hi all, I'm trying to clean up and reconfigure fair share on a slurm 20.11.9 production cluster after some trial and error before I started looking into it. I don't know the full story and need to pick up here. Fair share is enabled with default settings and not customised. It looks a bit like it was enabled by accident and relevant options are undefined/at default.

As a first step I would like to understand the current state. Executing sshare includes output like this (output shortened but complete for the two relevant accounts):

Account User Partition RawShares NormShares RawUsage EffectvUsage FairShare
-------- ---------- ------------ ---------- ----------- ----------- ------------- ----------
root 0.000000 1002501 1.000000
.root root 1 0.083333 0 0.000000 1.000000
.A1 1 0.083333 0 0.000000
..A1 U1 P1 1 0.166667 0 0.000000 0.873684
..A1 U2 P1 1 0.166667 0 0.000000 0.873684
..A1 U3 P1 1 0.166667 0 0.000000 0.873684
..A1 U3 P2 1 0.166667 0 0.000000 0.873684
..A1 U4 P3 1 0.166667 0 0.000000 0.873684
..A1 U4 P1 1 0.166667 0 1.000000 0.821053 <== What is going on here??
.A2 1 0.083333 0 0.000000
..A2 U5 P2 1 0.142857 0 0.000000 1.000000
..A2 U5 P1 1 0.142857 0 0.000000 1.000000
..A2 U6 P4 1 0.142857 0 0.000000 1.000000
..A2 U6 P1 1 0.142857 0 0.000000 1.000000
..A2 U6 P2 1 0.142857 0 0.000000 1.000000
..A2 U7 P1 1 0.142857 0 0.000000 1.000000
..A2 U7 P2 1 0.142857 0 0.000000 1.000000

User U4 is not a member of any other account.

I understand everything about this output except the line I marked. Both accounts A1 and A2 have zero usage, yet, for user U4 on partition P1 we have effective usage 1.0, screwing the fair share factors up for everyone in this account. As far as I can tell, both accounts should look identical with a fair share factor of 1 for every user.

I'm grateful for any pointer for what to look for.

Best regards,
Frank

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[Frank Schilder via slurm-users]

Looks like its an unclean handling of a "0/0" somewhere when RawUsage=0 for an entire account.

The issue disappears as soon as there is some usage. It can be difficult though to get some usage into the account with such a fair share penalty. In our case, we reorganised the accounts and the issue disappeared for now.

Best regards,

Frank

---

From: fr...@adm.ku.dk <fr...@adm.ku.dk>
Sent: 14 April 2025 13:37
To: slurm...@lists.schedmd.com
Subject: [slurm-users] Strange output of sshare