100Mbps Ethernet Speed/Efficiency

Neall neall at haughtmail.com
Tue Apr 6 21:18:11 UTC 2004

>> 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

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