Date: Sun, 12 Apr 2009 16:21:19 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Yuri <yuri@rawbw.com> Cc: freebsd-questions@freebsd.org Subject: Re: Why USB harddrive is so slow under FreeBSD? Message-ID: <20090412212118.GE90152@dan.emsphone.com> In-Reply-To: <49E246EC.50702@rawbw.com> References: <49E246EC.50702@rawbw.com>
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In the last episode (Apr 12), Yuri said: > I have FreeBSD-71 running with USB controller: > uhci0: <VIA 83C572 USB controller> port 0xa800-0xa81f irq 21 at device 16.0 on pci0 > > I connected to it Toshiba USB hard drive HDDR500E03X: > umass0: <Toshiba External USB HDD, class 0/0, rev 2.00/1.03, addr 2> on uhub4 > da0: <Toshiba External USB HDD 1.03> Fixed Direct Access SCSI-4 device > > When I try to copy data with 'dd if=/dev/da0s1 of=/dev/null count=10000' > it only achieves has 0.65MB/s transfer speed. > > What's wrong, why is it so slow? Increase your blocksize. dd's default is 512 bytes. Try bs=64k -- Dan Nelson dnelson@allantgroup.com
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