From owner-freebsd-questions@FreeBSD.ORG Mon Apr 13 00:31:14 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E80CD10656C0 for ; Mon, 13 Apr 2009 00:31:14 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from ch-smtp01.sth.basefarm.net (ch-smtp01.sth.basefarm.net [80.76.149.212]) by mx1.freebsd.org (Postfix) with ESMTP id A1B0F8FC1F for ; Mon, 13 Apr 2009 00:31:14 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from c83-255-48-78.bredband.comhem.se ([83.255.48.78]:51101 helo=falcon.midgard.homeip.net) by ch-smtp01.sth.basefarm.net with esmtp (Exim 4.69) (envelope-from ) id 1LtA4s-0005HN-5g for freebsd-questions@freebsd.org; Mon, 13 Apr 2009 02:31:12 +0200 Received: (qmail 69082 invoked from network); 13 Apr 2009 02:31:08 +0200 Received: from owl.midgard.homeip.net (10.1.5.7) by falcon.midgard.homeip.net with ESMTP; 13 Apr 2009 02:31:08 +0200 Received: (qmail 16604 invoked by uid 1001); 13 Apr 2009 02:31:08 +0200 Date: Mon, 13 Apr 2009 02:31:08 +0200 From: Erik Trulsson To: Yuri Message-ID: <20090413003108.GA16568@owl.midgard.homeip.net> References: <49E246EC.50702@rawbw.com> <20090412212118.GE90152@dan.emsphone.com> <49E262E6.6010206@rawbw.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49E262E6.6010206@rawbw.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-Originating-IP: 83.255.48.78 X-Scan-Result: No virus found in message 1LtA4s-0005HN-5g. X-Scan-Signature: ch-smtp01.sth.basefarm.net 1LtA4s-0005HN-5g e8c4741f9607abc3a41d12aa00bb0133 Cc: Dan Nelson , freebsd-questions@freebsd.org Subject: Re: Why USB harddrive is so slow under FreeBSD? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Apr 2009 00:31:15 -0000 On Sun, Apr 12, 2009 at 02:53:42PM -0700, Yuri wrote: > Dan Nelson wrote: > > > > Increase your blocksize. dd's default is 512 bytes. Try bs=64k > > > > This works, I am getting 25-27 MB/s. Still lower than this device > supports (~50MB/s). > I guess because this VIA controller is very old. Although the theoretical max speed of USB 2.0 is 60MB/s it is not actually possible to reach that speed. In practice the best transfer speed one can get over USB is 35-40 MB/s and most of the time not even that. Anything over 30MB/s with USB should be considered quite good, so the 25-27MB/s you are seeing are actually not all that bad. Some other controller *might* give you a few more MB/s but probably not more than that. -- Erik Trulsson ertr1013@student.uu.se