<div class="__aliyun_email_body_block"><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">Thanks for the comments, I do checked the cpu and memory using rate. It seems they are not the reason. The highest using rate is around fifteen pecent. I run two named in two process, may this be a reason? </div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;"><br data-mce-bogus="1"></div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">Best regards</div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">Runxia Wan</div><blockquote><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">------------------------------------------------------------------</div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">发件人：Darcy Kevin (FCA) <kevin.darcy@fcagroup.com></div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">发送时间：2014年11月8日(星期六) 05:53</div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">收件人：bind-users@lists.isc.org <bind-users@lists.isc.org></div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;">主 题：RE: Unexpected srrt in loopback</div><div style="font-family:Tahoma,Arial,STHeiti,SimSun;font-size:14px;color:#000000;"><br></div>
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<p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: #002060;">The network transit time over software loopback should be minimal, but network transit time isn’t the only thing which contributes to overall RTT.</span></p>
<p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: #002060;"> </span></p>
<p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: #002060;">Sounds like your named process is struggling to keep up with 5000 QPS. Have you looked at the memory, CPU? Are you running with a single thread, or multiple
threads? Are you bumping into operating-system limits (which are, depending on platform, tunable in named.conf)? There could be a lot of reasons why named gets backed up in processing requests, and these aren’t necessarily evident from doing a simple dig against
an otherwise-idle named instance.</span></p>
<p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: #002060;"> </span></p>
<p class="MsoNormal"><span style="font-size: 11.0pt;font-family: Calibri , sans-serif;color: #002060;"> - Kevin</span></p>
<p class="MsoNormal"><span style="color: black;"> </span></p>
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<p class="MsoNormal"><b><span style="font-size: 10.0pt;font-family: Tahoma , sans-serif;">From:</span></b><span style="font-size: 10.0pt;font-family: Tahoma , sans-serif;"> bind-users-bounces@lists.isc.org [mailto:bind-users-bounces@lists.isc.org]
<b>On Behalf Of </b>???<br>
<b>Sent:</b> Tuesday, November 04, 2014 4:39 AM<br>
<b>To:</b> bind-users@lists.isc.org<br>
<b>Subject:</b> Unexpected srrt in loopback</span></p>
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<p class="MsoNormal"></p> <p></p>
<p><span style="font-family: Calibri , sans-serif;">Hi everyone, I try to set up an authentic bind server in the loopback address(127.0.0.1) in our recursive server of</span>
<a><span style="font-family: Calibri , sans-serif;">our</span></a> <span style="font-family: Calibri , sans-serif;">
testbed for test reason. When I send a large number of junk queries(5000QPS), the srrt of loopback server in cash is unexpectedly large. Does anyone know the reason?</span>
<span style="font-family: Calibri , sans-serif;">The</span> <span style="font-family: Calibri , sans-serif;">
srrt is normal when I dig or</span> <span style="font-family: Calibri , sans-serif;">
ping the loopback server by the way.</span></p><p></p>
<p><span style="font-family: Calibri , sans-serif;">The dump_cache.db’s content:</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; Address database dump</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">;</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 10.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::13 [srtt 212] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 8.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::11 [srtt 744] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 3.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::6 [srtt 171] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 9.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::12 [srtt 44] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 4.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::7 [srtt 64] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 13.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::16 [srtt 26] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 5.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::8 [srtt 29] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 12.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::15 [srtt 2054] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 6.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::9 [srtt 663] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 1.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::2 [srtt 550] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 11.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::14 [srtt 44] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 7.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::10 [srtt 918] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 2.root-servers.net [v4 TTL 10744] [v6 TTL 86344] [v4 nxrrset] [v6 success]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; 240c:f:1:122::5 [srtt 360] [flags 00002000] [ttl 1746]</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; Unassociated entries</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">;</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">; ::1 [srtt 689] [flags 00002000] [ttl 1745]</span></p><p></p>
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<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">Best Regards</span></p><p></p>
<p><span style="font-size: 10.0pt;font-family: Calibri , sans-serif;">Runxia Wan</span></p><p></p>
<p><br>
<span style="font-size: 10.0pt;color: #333333;">---------------<br>
Runxia Wan(Brian)</span></p><p></p>
<p><span style="font-size: 10.0pt;color: #333333;">Research Engineer<br>
BII Lab</span></p><p></p>
<p><span style="font-size: 10.0pt;color: #333333;">Beijing Internet Institute(BII)</span></p><p></p>
<p><span style="font-size: 10.0pt;color: black;"><a href="mailto:rxwan@biigroup.cn" target="_blank">rxwan@biigroup.cn</a></span></p><p></p>
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