[Beowulf] building Infiniband 4x cluster questions

[Gilad Shainer]

> 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