[Beowulf] Problems with a JS21 - Ah, the networking...

Chris Samuel csamuel at vpac.org
Sat Sep 29 19:02:00 PDT 2007

On Sat, 29 Sep 2007, Ivan Paganini wrote:

> I sniffed the network in the store nodes interface, and i got lots
> of TCP lost fragment, previos lost fragments, ack lost fragments
> and TCP window size full.

Some suggestions would be to check that all network interfaces are 
negotiating gigabit back to the switch, and that if you are using 
jumbo frames then all interfaces are indeed using jumbo frames.

A useful check to verify 2 way jumbo frames connectivity is by using 
the ping command, doing:

ping -c 1 -M do -s 8900 $hostname

should tell you whether or not it is working.

Best of luck!
Christopher Samuel - (03) 9925 4751 - Systems Manager
 The Victorian Partnership for Advanced Computing
 P.O. Box 201, Carlton South, VIC 3053, Australia
VPAC is a not-for-profit Registered Research Agency

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