On Wed, Jul 28, 2004 at 10:05:47AM -0400, J?nos scratched on the wall:
> If I could invest into a Workgroup Cluster from Apple, my first dilemma
> would be what interconnection to use.
Not really. The Wordgroup Cluster comes with all the hardware for a
GigE interconnect, including switches and network cables.
> Should I connect all the nodes
> to a Gbit Ethernet switch using the 2 built in Gbit interface or use
> the the two 800 Mbit/s Firewire connection to daisy chain them or to
> connect them to a Firewire Hub ?
You should be aware that OS X does not (yet) support "bound" interfaces
(without third party tools). That is to say, if you use both GigE
ports, your nodes will each have one 1Gb connection to two different
networks. You will not have one virtual 2Gb network interface. Same
is true of the Firewire ports.
Despite Apple's parading of Firewire for an HPC interconnect, I can't
figure out for the life of me why you would ever want to do that.
The only time it seems to make any sense to me is if you only have
two nodes and are doing point-to-point. Firewire is essentially a
shared media, and while you can buy Firewire "hubs" (basically port
repeaters) I don't think anyone makes a Firewire "switch" that does
bandwidth isolation. People claim Firewire has very low latency, but
so does Ethernet-- it is the TCP/IP stack that kills your latency
with traditional Ethernet/IP networks, not the physical wires-- and
that's going to be true of Firewire too.
Daisy chaining them isn't going to be easy. The ports on the
machine are not like the two ports on the back of a hard drive-- I
don't think you can chain machines together and have them see one
large "link." I also suspect you'd would be hard pressed to find
a 24 port Firewire hub.
Am I missing something? Anyone have any good reasons to use Firewire?
> The cluster would have minimum 12
> nodes and do mostly bio-informatics related number crunching and
> statistical computation.
With that many nodes, I'd definitely use Ethernet. 16 (or 32) port
GigE switches with full capacity backplanes are not that rare
these days, and will provide a great deal more capacity than the
Firewire solution. Most Bioinformatics doesn't require extremely
fast low-latency interconnects anyways.
-j
--
Jay A. Kreibich | Integration & Software Eng.
email@hidden | Campus IT & Edu. Svcs.
<http://www.uiuc.edu/~jak> | University of Illinois at U/C
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