[Beowulf] is ethernet network proper for a 50-node Beowulf cluster?

Mark Hahn hahn at mcmaster.ca
Thu Apr 26 21:29:22 PDT 2007

> I want to build a Beowulf cluster with 50 computing nodes.

these days, that's a pretty small cluster, and shouldn't present
any big problems.

>> From network point of view, is Ethernet network with gigabit 
>> interconnection
> OK?

it depends, of course!  is gbe adequate for the level of communication you
expect among nodes?  are you really asking about whether 50x gbe will
create a hotspot going to a single fileserver or uplink or something?

> (Due to our some problems in using Myrinet and Infiniband , we prefer not to
> use thse two style of network)

one can create a perfectly respectable, good-performing cluster with 
gigabit.  modest-price switches are only available in certain sizes,
though - 48pt is common, and there are some switches with ~4 more ports,
and some with 10G uplinks available.  since you're probably spending 
at least $50k on the nodes, a $1500 10G nic on a hotspot fileserver 
might make a lot of sense, though you can get some benefit from simply using
multiple links from the server.

it's common for nodes to have 2 Gb ports, and tempting to try to take 
advantage of them.  if bandwidth is a concern, this may be an obvious 
tweak.  2pt/node can also give some interesting network topologies - 
the classic flat-network-neighborhood lets you plug 36 nodes into 
three 24pt switches, for instance.  there are other options that might 
make sense if certain sizes of switches are available cheaply...

regards, mark hahn.

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