[Beowulf]Infrastruture planning for small HPC 40/100 gigabyet eyhernet or Infiniband?

Nifty niftyompi Mitch niftyompi at niftyegg.com
Mon Jul 28 16:56:58 PDT 2008

On Mon, Jul 28, 2008 at 10:51:30AM +0200, Eugen Leitl wrote:
> On Sun, Jul 27, 2008 at 07:19:56PM -0700, Jim Lux wrote:
> > bear in mind that ordinary ethernet both coax and twisted pair is  
> > galvanically isolated.
> This is strange, because I've seen (small) sparks and received (mild)
> shocks from both, in two different locations. 
> As you say, http://www.apcmedia.com/salestools/FLUU-5T3TLT_R1_EN.pdf
> claims Ethernet is immune, yet I've read somewhere that Gigabit ethernet
> is more susceptible than Fast Ethernet. I've got (cheap) UPSen for
> almost all equipment, maybe they're the problem and not the switching
> power supplies.
> In any case I'll have an electrician diagnose the problem. Unfortunately,
> I anticipate his solution would involve pulling through a new large-crossection
> ground wire to several locations. It is at this point that lack of wall
> conduits will become quite painful.

Tell us more about your UPS setup.

Uninteruptible Power Supply boxes can do bad
things with power and ground.    Multiple
UPSen are sometimes hard to install correctly
it is easy to have 'earth' float....

	T o m  M i t c h e l l 
	Looking for a place to hang my hat.

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