Re: Tuning Linux for faster high-latency outbound transfers

From: Matt Zagrabelny
Date: Wed Jan 27 2010 - 09:50:53 EST

On Wed, 2010-01-27 at 11:45 +0100, Ketil Froyn wrote:
> Hi,
> I am based in Norway, and I'm benchmarking upload and download speeds
> to and from a US site (Rackspace Cloud Files). I'm on a 1Gbit link
> with a 100Mbit firewall limiting my speeds, but I routinely see both
> uploads and downloads at 20Mbit, and spikes up to 50Mbit. Ping latency
> between my site and the US site is about 170ms.
> The speeds I'm seeing for single large file transfers when benchmarking are:
> uploads: 90kb/s - 140kb/s
> downloads: 450kb/s - 500kb/s

So are you seeing 20Mb/s or 90 - 140 and 450 - 500 kb/s ?

How many hops away are you from the destination system?

Are you sure there is no shaping, throttling, or other contention
(besides the firewall) between your system and the destination?

Use iperf (aptitude install iperf) to saturate the link. You can send
both TCP and UDP packets/streams.

Matt Zagrabelny - mzagrabe@xxxxxxxxx - (218) 726 8844
University of Minnesota Duluth
Information Technology Systems & Services
PGP key 4096R/42A00942 2009-12-16
Fingerprint: 5814 2CCE 2383 2991 83FF C899 07E2 BFA8 42A0 0942

He is not a fool who gives up what he cannot keep to gain what he cannot
-Jim Elliot

Attachment: signature.asc
Description: This is a digitally signed message part