beowulf  

Re: [Beowulf] How to configure a cluster network

Patrick Geoffray
Thu, 24 Jul 2008 16:14:31 -0700

Hi Mark,

Mark Hahn wrote:
With any network you need to avoid like the plauge any kind of loop,
they can cause weird problems and are pretty much unnessasary. for

well, I don't think that's true - the most I'd say is that given

It is kind of true for wormhole switches, you can deadlock if you have loops (direct of indirect). The subnet manager / mapper will often prune some loopy links to be able to generate deadlock-free routes in polynomial time. So, you could have links that are just not used by any routes in funky topologies. Ethernet spanning tree is the most extreme paranoia, it will always prune all links but one between 2 switches (modulo link aggregation).

Patrick
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