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<div class="moz-cite-prefix">On 09/22/2014 08:16 PM, Khalid
Baheyeldin wrote:<br>
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<blockquote
cite="mid:CA+TuoW1nB67tX3mEVg7e1s0OZ-6KbQPisu5rBH6SHJhVbfX_hw@mail.gmail.com"
type="cite">
<div dir="ltr">On Mon, Sep 22, 2014 at 7:59 PM, William Park <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:opengeometry@yahoo.ca" target="_blank">opengeometry@yahoo.ca</a>></span>
wrote:<br>
<div class="gmail_extra">
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"><span class="">
</span>- What kind of test?<br>
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<div><br>
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<div>Copying around 100GB worth of files, most of them
multi-gigabyte in size, from one disk to the other. Using
rsync, while the files do not exist on the target<br>
<br>
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<div>rsync -av /mnt/disk1/ /mnt/disk2 <br>
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<div dir="rtl"> <br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
- Sequential, random?<br>
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<div>Sequential.<br>
<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
- DC or USB powered?<br>
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<div><br>
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<div>USB powered. Both disks are portable (one Toshiba
Canvio, the other Seagate Expansion.<br>
<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
- Intel, AMD? -- Intel 3Gbps chipset is better than AMD
6Gbps. </blockquote>
<div><br>
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<div>This is an AMD machine.<br>
<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">You see the difference
under heavy load, like 4 VMs in </blockquote>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hyper-V as I'm doing
now.<br>
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<div><br>
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<div>Bare metal in my case, no virtualization, and no other
load on the machine.<br>
<br>
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<div>Seems there is a partial answer here:<br>
<br>
<a moz-do-not-send="true"
href="http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html">http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html</a><br>
<br>
</div>
<div>Spinning disks can only do 114MB/s (7200 RPM that is).
SSDs can do 200 MB/s.<br clear="all">
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</blockquote>
59MB/s sequential read speed is entirely reasonable for a 5400RPM
drive - regardless of how it is connected.<br>
<br>
In order to get past the 200MB/s limit with a typical USB3
connection, one has to be more creative eg.<br>
<a class="moz-txt-link-freetext" href="http://marc-abramowitz.com/archives/2007/02/17/getting-good-performance-out-of-usb-hard-drives-in-linux/">http://marc-abramowitz.com/archives/2007/02/17/getting-good-performance-out-of-usb-hard-drives-in-linux/</a><br>
Tuning max_sectors should reduce CPU load (probably your bottleneck
for fast USB transfer - watch "top") and increase sequential
performance efficiency.<br>
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