<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m working on 6.5 running with 2.6.32-431.el6.x86_64, my multipath.conf if configured with both rr_min_io and rr_min_io_rq, running 64k 100% write load to my storage system using 8 paths over FC (“queue-length” policy).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I found [1] that rr_min_io is deprecated in favor of rr_min_io_rq, but playing with these values show that different rr_min_io_rq have no influence on performance in my env, however, different values of rr_min_io have huge influence on
the average latency I get for the same iops.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Am I missing something?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[1] <a href="https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/DM_Multipath/MPIO_Overview.html">
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/DM_Multipath/MPIO_Overview.html</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">device-mapper-libs-1.02.79-8.el6.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-event-libs-1.02.79-8.el6.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-persistent-data-0.2.8-2.el6.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-1.02.79-8.el6.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-event-1.02.79-8.el6.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-multipath-libs-0.4.9-72.el6_5.3.x86_64<o:p></o:p></p>
<p class="MsoNormal">device-mapper-multipath-0.4.9-72.el6_5.3.x86_64<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</body>
</html>