From owner-freebsd-net@FreeBSD.ORG Wed Nov 21 16:47:25 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6B6E7C1B for ; Wed, 21 Nov 2012 16:47:25 +0000 (UTC) (envelope-from m.e.sanliturk@gmail.com) Received: from mail-vb0-f54.google.com (mail-vb0-f54.google.com [209.85.212.54]) by mx1.freebsd.org (Postfix) with ESMTP id 195D28FC08 for ; Wed, 21 Nov 2012 16:47:24 +0000 (UTC) Received: by mail-vb0-f54.google.com with SMTP id l1so9765502vba.13 for ; Wed, 21 Nov 2012 08:47:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=yNX+W1U9inAzhWzMBu4kdNZ6kdpPBK37o5Sv40Js588=; b=civrOjajbP8/PBag5lmjWC1qLmlEUH+NYVqO+d2Xs1/R90JLm6MVWOcO/nc0oUjJW1 mOGFPBU/scEcUbgDjh823b/YZcGSChbDN4D1T1yXmzGDKvlHPg98ZOkFZGofaGORspuZ bmIeXubJ3kcXinfxTwAzx61hhHGAYEHcHtXvy27at0pWoe68msXrOOdwVvtpAZfYJroL 5SXr3X1bJ3zWwu9xiscJ8OSgSLhUJBNiZ0rB6fSI/fN49CUxWkA3W8FO/S20mjxzjDU1 x71yVHhyprdWgY3dFnwwiS/n4F+eqWaMVWDQ468INWXB0JkFVRjoTFYfOWfQAjDKrpdq Gk/w== MIME-Version: 1.0 Received: by 10.58.161.113 with SMTP id xr17mr27988330veb.3.1353516444049; Wed, 21 Nov 2012 08:47:24 -0800 (PST) Received: by 10.58.218.35 with HTTP; Wed, 21 Nov 2012 08:47:23 -0800 (PST) In-Reply-To: <50ACF62C.8000408@mpeters.org> References: <50ACF62C.8000408@mpeters.org> Date: Wed, 21 Nov 2012 08:47:23 -0800 Message-ID: Subject: Re: Low Bandwidth on intercontinental connections From: Mehmet Erol Sanliturk To: Marc Peters Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: freebsd-net@freebsd.org X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Nov 2012 16:47:25 -0000 On Wed, Nov 21, 2012 at 7:41 AM, Marc Peters wrote: > Hi list, > > we are experiencing low throughput on interncontinental connections with > our FreeBSD Servers. We made several tests and are wondering, why this > would be. The first tests were on an IPSEC VPN between our datacenter in > DE and Santa Clara, CA. We are connected with two gigabit uplinks in > each DC. Pushing data by scp between our FreeBSD servers takes ages. > Starting with several MB/s it drops to 60-70KB/s: > ..... I do not have any answer to your question , but I want to share one my experiences . I Linux ( KDE ) I was copying a hard disk contents to another drive by using Dolphin . At the beginning it was very fast , but over time its speed reduced to a few kilobytes per second . It listed completion time left as months . I inspected why this is the case . The reason was the following : On each file it is copied , the Dolphin was producing approximately 1 Kilobyte memory leak . After copying more than one million file , all of the memory exhausted and it started to swap memory to hard disk swap space which reduced copy speed to a few kilobytes per second . I stopped the Dolphin and copied small directory groups by restarting the Dolphin . This cured the problem because on each exit , all of the leaked memory by Dolphin has been disposed ( where "Undo" item of Dolphin menu was disabled means memory is not reserved for undo ). Please study your data transfer software for such a possibility . It may not be problematic in Linux but FreeBSD version may have some trouble points . There is another possibility : Graceful degradation . http://en.wikipedia.org/wiki/Graceful_degradation http://en.wikipedia.org/wiki/Fail_soft A program part may produce graceful degradation over time or processed data : For example , assume a list is searched by sequentially . When list length grows , search times also grows linearly and produces a degradation although there is no any error in the process . You may study your system with respect to such a process . These are the possibilities which come to my mind . Thank you very much . Mehmet Erol Sanliturk