[Beowulf] How to configure a cluster network

[Nifty niftyompi Mitch]

On Thu, Jul 24, 2008 at 07:27:56PM +0100, andrew holway wrote:
> Sender: andrew.holway at googlemail.com
> 
> > Your most cost effective solution will be a large port count switch.
> > Most are not 'ideal' but they are close to ideal and cost effective.
> 
> That is not really the case in practice;
> 
> You can buy a Mellanox 144-Port Modular InfiniBand DDR Switch
> (60-Ports enabled) for around 22k EUR or so
> 
> the 24 port switches are around 2k EUR
> 
> As most people dont need anything like the full 16 Gbit/s bandwidth
> you can connect up your 50 ports for about 13/14k EUR

60 ports on a 144 port box.... Hmmm...
You are paying for the empty holes and future expansion.

If you  need 144 ports a single switch will be be more cost effective
than a gaggle of 24 ports gathered together into a tangled hairy cable ball with
144 ports exposed.  

Your point about "most people don't need" is important!   With large
multi core, multiple socket systems external and internal bandwidth
can be interesting to ponder.

Bandwidth, message rate and latency all come to play and differing applications
need more or less of each to go fast.

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