Date: Mon, 13 Apr 2009 02:31:08 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Yuri <yuri@rawbw.com> Cc: Dan Nelson <dnelson@allantgroup.com>, freebsd-questions@freebsd.org Subject: Re: Why USB harddrive is so slow under FreeBSD? Message-ID: <20090413003108.GA16568@owl.midgard.homeip.net> In-Reply-To: <49E262E6.6010206@rawbw.com> References: <49E246EC.50702@rawbw.com> <20090412212118.GE90152@dan.emsphone.com> <49E262E6.6010206@rawbw.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20090413003108.GA16568>