[Beowulf] Intel buys QLogic InfiniBand business

Mark Hahn hahn at mcmaster.ca
Sat Jan 28 13:28:09 PST 2012

>>> So I wonder why multiple OEMs decided to use Mellanox for on-board
>>> solutions and no one used the QLogic silicon...
>> That's a strange argument.
> It is not an argument, it is stating a fact.

you are mistaken.  you ask a pointed question - do not construe it 
as a statement of fact.  if you wanted to state a fact, you might say:
"multiple OEMs decided to use Mellanox and none have used Qlogic".

by stating this, you are implying that Mellanox is superior in some way,
though another perfectly adequate explanation could be that Qlogic 
didn't offer their chips to OEMs, or did so at a higher price.  (in fact,
the latter would suggest the possibility that Qlogic chips are actually
worth more.)  note my use of subjunctive here.

in reality, Mellanox is the easy choice - widely known and used,
the default.  OEMs are fond of making easy choices: more comfortable
to a lazy customer, possibly lower customer support costs, etc.

this says nothing about whether an easy choice is a superior solution 
to the customer (that is, in performance, price, etc).

> If someone claims that a product provide 10x better performance, best fit
>etc., and from the other side it has very little attraction, something does
>not make dense.

I saw no 10x performance claim here.  there was some casual mention
of a situation where Qlogic QDR performs similar to Mellanox FDR.

>good validation for InfiniBand as a leading solution for any server and
>storage connectivity.

besides Lustre, where do you see IB used for storage?

> Going into a bit more of a technical discussion... QLogic way of networking
>is doing everything in the CPU, and Mellanox way is to implement if all in
>the hardware (we all know that).

this is a dishonest statement: you know that QLogic isn't actually trying
to do *everything* in the CPU.

> The second option is a superset, therefore
>worse case can be even performance.

this is also dishonest: making the adapter more intelligent clearly
introduces some tradeoffs, so it's _not_ a superset.  unless you are 
claiming that within every Mellanox adapter is _literally_ the same 
functionality, at the same performance, as is in a Qlogic adapter.

>> Maybe we could have a few less attacks, complaining and hand waving and
>> more useful information?  IMO Greg never came across as a commercial
>> (which beowulf list isn't an appropriate place for), but does regularly contribute
>> useful info.  Arguing market share as proof of performance superiority is just
>> silly.
> I am not sure about that... quick search in past emails can show amazing things...
> I believe most of us are in agreement here. Less FUD, more facts.

"facts" in this context (as opposed to FUD, armwaiving, etc) must be 
dispassionate and quantifiable.  not hyperbole and suggestive rhetoric.

out of curiosity, has anyone set up a head-to-head comparison
(two or more identical machines, both with a Qlogic and a Mellanox card of
the same vintage)?

regards, mark hahn.

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