[Beowulf] NFS over RDMA

[Nifty niftyompi Mitch]

On Fri, Oct 24, 2008 at 03:31:19PM +0100, John Hearns wrote:
> 
>    Joe has just mentioned NFS over RDMA, a subject which I have somewhat
>    of a passing interest in.
> 
>    What's the perceived wisdom on it? Biggest, best shiny new thing on the
>    block? Works just fine?

There are some hardware cards out there, both Infiniband and 10Ge,
that are designed with RDMA as an optimized way to move data.
If you have these RDMA optimized cards the new shiny NFS over RDMA
may be for you.  Others will have to  comment on the stability
experiences they are having.  You will have to match their reports
to your distro and decide on the next step.

Some source tree searching  and web searching will let you discover
how new it is and how much special handling it will take at your
site.  My tolerance indicator tells me that this is a tad new for
NFS but new now is not new tomorrow. 

Clearly the way to think about it is that it is a low level perhaps
vendor specific transport optimization that will help or hinder depending
on the site situation.

My bias is that vendor specific transport tinkering for fundamental 
resources like NFS is a risk.   I would rather the vendor tune foundation
things like TCP/IP and not poke at NFS in ways that bypass TCP/IP.

>    Or should it be in the basement inside a locked filing cabinet in a
>    disused lavatory with a sign saying Beware of the Leopard?

I doubt that it is that bad ;-).   

Some good vendors are hacking on it.

The hard part is evaluation, testing and tomorrows integration with
the next interconnect update.

-- 
	T o m  M i t c h e l l 
	Found me a new hat, now what?