[openib-general] Newbie Questions Regarding How To Start

[Roland Dreier]

    Uncle>   Can infiniband function properly in a physical point to
    Uncle> point topology?  I would prefer to not invest in switches
    Uncle> if it's not entirely necessary.  The documentation I've
    Uncle> glanced at so far seems to indicate that infiniband is
    Uncle> logically point-to-point.  But the diagrams representing
    Uncle> physical topology all seem to have switches.  Other than
    Uncle> obviously not being able to communicate across a fabric, is
    Uncle> there functionality missing from a point-to-point topology?
    Uncle> Does it even work?
  
Yes, this works.  You will still need to run a subnet manager on one
or both of the two hosts in your fabric.  OpenSM will work fine.

    Uncle>   What's the best HCA card for me?  I'm drawn to Mellanox
    Uncle> MT23108-based systems because OpenIB seems to support them
    Uncle> well
    Uncle> (https://openib.org/tiki/tiki-index.php?page=MellanoxHcaFirmware).

Yes, I think MT23108 HCAs are your only choice.  I don't know of any
other PCI-X HCAs.

    Uncle> I'm considering purchasing two HP NC570C cards
    Uncle> (http://h30094.www3.hp.com/product.asp?sku=2603660&), which
    Uncle> are based on that Mellanox chip.  Does anybody know if
    Uncle> those cards would be functional in non-hp gear?  In other
    Uncle> words, does HP have their own proprietary goodies in the
    Uncle> cards that would cause them to break in generic systems
    Uncle> such as what I have?  Are there better cards for me?

I would guess that all MT23108-based cards are pretty much the same,
but you would have to confirm with HP to find out for sure.  Using
them in non-HP systems might affect your ability to get support if
they don't work.  You could also consider the Cisco SFS-HX4XCI2-LTM1=
HCA for example, and I'm sure lots of other vendors have PCI-X HCAs
available as well.

Probably the best thing to do would be to go for the best price and
availability that you can find.

 - R.