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Hi Jonathan,</div>
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I assume this is using GNR, right ? which Scale version are you using ? </div>
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Background: there was a known issue with the bandwidth_low event when GNR is used. </div>
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best regards<br>
<br>
Mathias Dietz</div>
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Storage Scale RAS Architect <br>
<br>
IBM Deutschland Research & Development GmbH</div>
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Vorsitzender des Aufsichtsrats: Wolfgang Wendt</div>
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Geschftsfhrung: David Faller</div>
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Sitz der Gesellschaft: Bblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> gpfsug-discuss <gpfsug-discuss-bounces@gpfsug.org> on behalf of Jonathan Buzzard via gpfsug-discuss <gpfsug-discuss@gpfsug.org><br>
<b>Sent:</b> Tuesday, August 25, 2026 4:47 PM<br>
<b>To:</b> gpfsug-discuss <gpfsug-discuss@gpfsug.org><br>
<b>Cc:</b> Jonathan Buzzard <jonathan.buzzard@strath.ac.uk><br>
<b>Subject:</b> [EXTERNAL] [gpfsug-discuss] Bandwidth low</font>
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I have a number of new DSS-G servers that are showing a bandwidth_low <br>
tip. Searching suggests this is something to do with a large pagepool <br>
and insufficient network bandwidth.<br>
<br>
Except all these servers have dual 200Gbps Ethernet connections in a <br>
802.3ad bond to two SN3700m switches in an MLAG. After lots of digging <br>
around the maxMBpS is set to 80000 which is what it should be.<br>
<br>
I figure as far as Ethernet networking goes this is about as good as it <br>
gets. It is way better than our old DSS-G which for a long time only had <br>
dual 40Gbps Ethernet on each node, though this is now been maxed out at <br>
quad 40Gbps Ethernet on each node. Those nodes are not showing the tip <br>
despite their lower total network bandwidth.<br>
<br>
The only thing I can think is that 200Gbps is an unusual Ethernet speed <br>
which is confusing the calculations? I know Lenovo could not supply <br>
200Gbps Ethernet optics and DAC's and I had to supply my own.<br>
<br>
<br>
JAB.<br>
<br>
-- <br>
Jonathan A. Buzzard Tel: +44141-5483420<br>
HPC System Administrator, ARCHIE-WeSt.<br>
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG<br>
<br>
<br>
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