<div dir="ltr"><div>Greetings Jessica,</div><div><br></div><div>I'm not sure I am correctly understanding the behavior "robinhood activity floods the MDT". The robinhood program as you (and I) are using it is consuming the MDT CHANGELOG via a reader_id which was assigned when the CHANGELOG was enabled on the MDT. You can check the MDS for these readers via "lctl get_param mdd.*.changelog_users". Each CHANGELOG reader must either be consumed by a process or destroyed otherwise the CHANGELOG will grow until it consumes sufficient space to stop the MDT from functioning correctly. So robinhood should consume and then clear the CHANGELOG via this reader_id. This implementation of robinhood is actually a rather light-weight process as far as the MDS is concerned. The load issues I encountered were on the robinhood server itself which is a separate server from the Lustre MGS/MDS server.</div><div><br></div><div>Just curious, have you checked for multiple reader_id's on your MDS for this Lustre file system?</div><div><br></div><div>P.S. My robinhood configuration file is using nb_threads = 8, just for a data point.</div><div><br></div><div>Cheers,</div><div>megan</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, May 18, 2017 at 2:36 PM, Jessica Otey <span dir="ltr"><<a href="mailto:jotey@nrao.edu" target="_blank">jotey@nrao.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hi Megan,<br>
</p>
<p>Thanks for your input. We use percona, a drop-in replacement for
mysql... The robinhood activity floods the MDT, but it does not
seem to produce any excessive load on the robinhood box...</p>
<p>Anyway, FWIW...<br>
</p>
<p>~]# mysql --version<br>
mysql Ver 14.14 Distrib 5.5.54-38.6, for Linux (x86_64) using
readline 5.1<br>
</p>
<p>Product: robinhood<br>
Version: 3.0-1<br>
Build: 2017-03-13 10:29:26<br>
<br>
Compilation switches:<br>
Lustre filesystems<br>
Lustre Version: 2.5<br>
Address entries by FID<br>
MDT Changelogs supported<br>
<br>
Database binding: MySQL<br>
</p>
<p>RPM: robinhood-lustre-3.0-1.<wbr>lustre2.5.el6.x86_64</p>
Lustre rpms:<br>
<p>lustre-client-2.5.5-2.6.32_<wbr>642.15.1.el6.x86_64_g22a210f.<wbr>x86_64<br>
lustre-client-modules-2.5.5-2.<wbr>6.32_642.15.1.el6.x86_64_<wbr>g22a210f.x86_64<br>
</p>
<br>
<div class="m_-8956838098082579714moz-cite-prefix">On 5/18/17 11:55 AM, Ms. Megan Larko
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>With regards to (WRT) Subject "Robinhood exhausting RPC
resources against 2.5.5 lustre file systems", what version
of robinhood and what version of MySQL database? I mention
this because I have been working with robinhood-3.0-0.rc1 and
initially MySQL-5.5.32 and Lustre 2.5.42.1 on
kernel-2.6.32-573 and had issues in which the robinhood server
consumed more than the total amount of 32 CPU cores on the
robinhood server (with 128 G RAM) and would functionally hang
the robinhood server. The issue was solved for me by
changing to MySQL-5.6.35. It was the "sort" command in
robinhood that was not working well with the MySQL-5.5.32.</div>
<div><br>
</div>
<div>Cheers,</div>
<div>megan</div>
</div>
<div class="gmail_extra"><br>
</div>
</blockquote>
<br>
</div>
</blockquote></div><br></div>