[Beowulf] cluster flexibility vs. design specificity, cluster vs. supercomputing

[Xu, Jerry]

Hi, All:
    
   I know lots experts here in this forum...so I am just keep posting and hope
somebody can give a response :-)

   Here is a non-technical question but question regarding a strategy to manage
growing cluster(s), it is about cluster flexibility vs. design specificity.
  
   Myself, prefer every cluster is specifically designed with "rooted" firmware
and even hardware design, and benchmarked with specific application. That is my
understanding of the cluster for supercomputing in scientific community.

    But, in real life, "cluster" diverges from "supercomputing", in order to
expand the cluster without being tangled by the product provider, and, in order
to managing a evolving cluster, we have to allow certain/great flexibility for
the cluster. in my mind, that is not really a supercomputing or "high
performance computing" for computing efficiency ((e.g. possible conflicts of
mixtures of hardwares within the cluster?) Or, I am just plain wrong.

   Any expert can clarify the confusion?  How can we independently (not being
tangled by specific vendor) expand and keep evolving the cluster but without
sacrificing the computing efficiency? Or, I just worry too much? Normally, if we
mix different hardwares together (like traditional beowulf cluster), how bad it
could be to affect the specifically designed cluster?

Thanks!!