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Le 25/01/2011 07:21, Michael Monnerie a écrit :
<blockquote cite="mid:201101250721.14716@zmi.at" type="cite">
<pre wrap="">On Dienstag, 18. Januar 2011 Cory Coager wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Also, I want to stress that I am only having performance issues with
one logical volume, the others seem fine.
</pre>
</blockquote>
<pre wrap="">
You're getting 40MB/s write speed and says that's fine? I get more
performance from a single SATA desktop drive. Your setup seems to suck
extremely somewhere.
It already starts with your dd speed. I started it on a virtualized VM
on an old, overloaded server and get:
# dd if=/dev/zero of=test.dd bs=1k count=1M
1048576+0 Datensätze ein
1048576+0 Datensätze aus
1073741824 Bytes (1,1 GB) kopiert, 10,9992 s, 97,6 MB/s
</pre>
</blockquote>
<br>
I would say this is melted with cache hit, isn't it ? (although I
agree it depends on the server's memory dedicated to FS cache)<br>
<br>
A real cache hit on a real server would give me at least 500 MB/s
(actually I get something around 1 GB/s)<br>
When it starts to be disk-constrained, on a standard SATA disk, I
get from 75 MB/s to 140 MB/s depending on the position of the AG I
hit.<br>
<br>
<br>
<div class="moz-signature">-- <br>
<font color="blue"><b>Mathieu Avila</b><br>
IT & Integration Engineer<br>
</font>
<a class="moz-txt-link-abbreviated" href="mailto:mathieu.avila@opencubetech.com">mathieu.avila@opencubetech.com</a><br>
<br>
OpenCube Technologies <a href="http://www.opencubetech.com">http://www.opencubetech.com</a><br>
Parc Technologique du Canal, 9 avenue de l'Europe<br>
31520 Ramonville St Agne - FRANCE<br>
Tel. : +33 (0) 561 285 606 - Fax : +33 (0) 561 285 635<br>
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