[Beowulf] Infiniband: MPI and I/O?

[Bill Wichser]

Wondering if anyone out there is doing both I/O to storage as well as 
MPI over the same IB fabric.  Following along in the Mellanox User's 
Guide, I see a section on how to implement the QOS for both MPI and my 
lustre storage.  I am curious though as to what might happen to the 
performance of the MPI traffic when high I/O loads are placed on the 
storage. 

In our current implementation, we are using blades which are 50% 
blocking (2:1 oversubscribed) when moving from a 16 blade chassis to 
other nodes.  Would trying to do storage on top dictate moving to a 
totally non-blocking fabric?

Thanks,
Bill