[Beowulf] scratch File system for small cluster

Scott Atchley atchley at myri.com
Thu Sep 25 07:58:59 PDT 2008

On Sep 25, 2008, at 10:19 AM, Joe Landman wrote:

> We have measured NFSoverRDMA speeds (on SDR IB at that) at 460 MB/s,  
> on an RDMA adapter reporting 750 MB/s (in a 4x PCIe slot, so ~860 MB/ 
> s max is what we should expect for this).  Faster IB hardware should  
> result in better performance, though you still have to walk through  
> the various software stacks, and they ... remove efficiency ...  
> (nice PC way to say that they slow things down a bit :( )


Even though recent kernels allow rsize and wsize of 1 MB for TCP,  
RPCRDMA only supports 32 KB. This will limit your throughput some  
regardless of faster hardware.


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