[Beowulf] Need recommendation for a new 512 core Linux cluster

[Jeffrey B. Layton]

Mark Hahn wrote:
>> welcome) nfs-4.1 protocol support for supporting clients that don't have
>> to know the details of the distributed magic at work.
>
> so far, my understanding is that pnfs lets a naive client work 
> transparently
> only by routing the IO through the metadata server.  parallel-aware
> clients will distinguish between the MDS and content servers, and can 
> carry on parallel IO direct to the latter.

I'm pretty sure that the pNFS requires all clients and drivers to allow
parallel access from the clients to the storage outside of the metadata
server. While I haven't read the specs, I'm pretty sure this is true. If
the clients didn't allow parallel access to the storage outside of the
metadata server then it's not NFS 4.1. It's just plain NFS 3 or 4.

Jeff