[Beowulf] strange PXE reboot behavior

[Geoff Galitz]

Hello folks,


We have a strange problem.  We have 20 nodes with SE7501CW2
motherboards, and about 5 of them seem to fail their POST and reboot
only when the gigabit NIC is plugged into a gigabit switch.  If we
unplug it, the node functions normally.  If we plug it in after the 
system
comes up, it crashes immediately.

My only thought at this point is auto-negotiation, but I cannot seem to
turn off auto-negotiation on these motherboard/NIC combos.  Ethtool 
fails
to change the parameters on the cards.

Any other ideas?

-geoff





http://www.galitz.org