[Beowulf] building Infiniband 4x cluster questions

[Vincent Diepeveen]

Thanks for the very clear explanation Gilad!

You beated with just 2 lines entire wiki and lots of other homepages  
with endless of chatter :)

On Nov 7, 2011, at 6:19 PM, Gilad Shainer wrote:

>> hi John,
>>
>> I had read already about subnet manager but i don't really  
>> understand this,
>> except when it's only configuration tool.
>>
>> I assume it's not something that's critical in terms of bandwidth,  
>> it doesn't
>> need nonstop bandwidth from the machine & switch is it?
>
> The subnet management is just an agent in the fabric that give  
> identifiers to the ports and set the routing in the fabric (in case  
> of static routing). It will also discover new nodes once connected  
> to the fabric, or nodes that went down (in the later case, it can  
> modify the routing accordingly). The agent requires negligible  
> network resources, so no need to worry.  You can run the subnet  
> management from a server (head node for example using OpenSM for  
> example) or from one of the switches.
>
> Gilad
>