[Bio-Linux] Bandwidth cont.

[Tony Travis]

On 12/07/13 14:27, Tim Booth wrote:
> Hi,
> 
>> Have you tried nice'ing the download program?
>>
>>   nice -n 19 sftp ...
> 
> "Nice" only affects CPU scheduling priority.  It might help you to keep
> the ssh login responsive while the download is happening, but otherwise
> I can't see it doing much.  Unless you only have a single CPU core in
> the server it won't make any difference at all.

Hi, Tim.

I know that :-)

However, The way that "wget" and "sftp" limit bandwidth is by sleeping
between blocks as the transfer proceeds. You're right that it won't make
much difference on a system that is not limited by CPU resources.

>> To throttle at the hardware level, you could fit a 100Mbit NIC or
>> configure your switch to connect at 10/100Mbit instead of 1Gbit?
> 
> This would seem a little desperate.

Indeed...

> I think you need to experiment with the -l/--limit-rate option to wget
> as Tony suggested.  Maybe start at 1k/sec and try doubling the rate
> until you hit problems.

I think this is good advice, but as Alec said before he already tried
and if the way "wget" and "sftp" limit bandwidth is dependent on CPU
resources being limited then it won't have much effect. These modern
computers are just too fast for their own good ;-)

Bye,

  Tony.
-- 
Dr. A.J.Travis, University of Aberdeen, Institute of Biological and
Environmental Sciences, Cruickshank Building, St. Machar Drive, Aberdeen
AB24 3UU, Scotland, UK. tel +44(0)1224 272700, fax +44 (0)1224 272 396
http://www.abdn.ac.uk, mailto:tony.travis at abdn.ac.uk, skype:ajtravis