[gpfsug-discuss] Bandwidth low

[Jonathan Buzzard]

I have a number of new DSS-G servers that are showing a bandwidth_low 
tip. Searching suggests this is something to do with a large pagepool 
and insufficient network bandwidth.

Except all these servers have dual 200Gbps Ethernet connections in a 
802.3ad bond to two SN3700m switches in an MLAG. After lots of digging 
around the maxMBpS is set to 80000 which is what it should be.

I figure as far as Ethernet networking goes this is about as good as it 
gets. It is way better than our old DSS-G which for a long time only had 
dual 40Gbps Ethernet on each node, though this is now been maxed out at 
quad 40Gbps Ethernet on each node. Those nodes are not showing the tip 
despite their lower total network bandwidth.

The only thing I can think is that 200Gbps is an unusual Ethernet speed 
which is confusing the calculations? I know Lenovo could not supply 
200Gbps Ethernet optics and DAC's and I had to supply my own.


JAB.

-- 
Jonathan A. Buzzard                         Tel: +44141-5483420
HPC System Administrator, ARCHIE-WeSt.
University of Strathclyde, John Anderson Building, Glasgow. G4 0NG