100Mbps Ethernet Speed/Efficiency

[Laurence Orchard]

On Tue, 2004-04-06 at 22:18, Neall wrote:
> >> I'm wondering what's the maximum sustained transfer rate
> >> that one can experience when using a 100Mbps link?
> 
> I took the hard drives out of the picture.  I set up RAM disks on two
> different systems, and connected them via ethernet using NFS to cross
> mount them.  Then, I copied from the first system's RAM disk over
> ethernet, to the second system's RAM disk.  Granted, NFS is in the
> picture, but it would be using hard drives, too.
> 
> These numbers include NFS overhead (obviously):
> 
> 100 Mb file:
> 100/T: 11.335 MByte/Sec (averaged over many tests).
> 1000/T: 69.9 MByte/Sec.
> 
> Obviously, the 1000/T (gigabit) test would have immediately been
> bottlenecked by the drive transfer rates.  The 100/T rates are near
> theoretical.  Not sure where the 1000/T bottle neck is, but I used stock
> NFS parameters.  I may try to transfer via socket or rpc, but just haven't
> gotten there yet.  I figured most people transfer via NFS (or SAMBA)
> mounted drives, so wanted to start there.
> 
> Still, ~70 MByte/sec isn't shabby over gigabit ethenet via NFS.  Neall
> 
> 

Hi

have you considered putting the data file in a ram disk to overcome the
disk transfer overhead? assuming you have enough physical memory so you
don't hit swapping!

Laurence