[kwlug-disc] Fast transfer protocol?

Paul Nijjar paul_nijjar at yahoo.ca
Sun Oct 24 00:41:00 EDT 2010

On Fri, Oct 22, 2010 at 12:32:37PM -0400, Lori Paniak wrote:
> I tried this once upon a time.  I found it more difficult than I
> expected. Typical hardware - especially hard drives - cannot keep up to
> a gigabit link.  I used an FTP server running from a RAM disk.  Even
> then, the Atom CPU in the server had a hard time sustaining more than
> 60MB/sec of transfer. 
> In the end I concluded that I was testing the limits of my CPU and disk
> subsystem more than any network hardware.
> It is entirely possible your Windows client can write transferred files
> to disk at only 25MB/s (which is pretty good).

So I ended up testing with a program called iperf
(http://iperf.sourceforge.net) which appears to be a pretty standard
network testing tool. Because I am lazy I used precompiled versions,
which meant that there were version issues between the Windows version
(1.70) and the version on my Knoppix LiveCD (2.0.3 or something). 

The nice thing about iperf is that it does not interact with the disk. 

iperf works by having one machine act as a server and other machines
acting as clients. The clients connect to a server and pump data

It supports both Windows and Linux, although the Windows version is
some old precompiled version off the Internet. This means that
comparisons are not fair. 

I can pretty much max out my gigabit connection using iperf and two
Windows servers with built-in gigabit cards. Any other combination of
Windows/Linux maxes out at about 60% usage. 

Samba is indeed slow. I get better throughput with an FTP server. Disk
does indeed appear to be a limiting factor. 

On at least one machine (one with Windows and Linux) I found that
something in the operating system and/or version of iperf makes the
results pretty different. 

- Paul


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