[Beowulf] Varying performance across identical cluster nodes.

Christopher Samuel samuel at unimelb.edu.au
Sun Sep 10 16:53:00 PDT 2017

On 09/09/17 04:41, Prentice Bisbal wrote:

> Any ideas where to look or what to tweak to fix this? Any idea why this
> is only occuring with RHEL 6 w/ NFS root OS?

No ideas, but in addition to what others have suggested:

1) diff the output of dmidecode between 4 nodes, 2 OK and 2 slow to see
what differences there are in common (if any) between the OK & slow
nodes.  I would think you would only see serial number and UUID
differences (certainly that's what I see here for our gear).

2) reboot an idle OK and slow node node and immediately capture the
output of dmesg on both and then diff that.  Hopefully that will reveal
any differences in kernel boot options, driver messages, power saving
settings, etc, that might be implicated.

Good luck!
 Christopher Samuel        Senior Systems Administrator
 Melbourne Bioinformatics - The University of Melbourne
 Email: samuel at unimelb.edu.au Phone: +61 (0)3 903 55545

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