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<p>I saw something similar a good few years ago (ie on an older
version of GPFS). IIRC the issue was one of contention: one or
two served nodes were streaming IOs to/from the NSD servers and as
a result other nodes were exhibiting insane IO times. Can't be
more helpful though, I no longer have access to the system.</p>
<p>Regards,</p>
<p>J Martin Rushton MBCS<br>
</p>
<br>
<div class="moz-cite-prefix">On 04/10/18 20:54, Buterbaugh, Kevin L
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:50FD239F-E4D7-45EB-9769-DE7A0F3C4FA9@vanderbilt.edu">
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Hi All,
<div class=""><br class="">
</div>
<div class="">What does it mean if I have a few dozen very long
I/O’s (50 - 75 seconds) on a gateway as reported by “mmdiag
—iohist” and they all reference two of my eight NSD servers…</div>
<div class=""><br class="">
</div>
<div class="">… but then I go to those 2 NSD servers and I don’t
see any long I/O’s at all?</div>
<div class=""><br class="">
</div>
<div class="">In other words, if the problem (this time) were the
backend storage, I should see long I/O’s on the NSD servers,
right?</div>
<div class=""><br class="">
</div>
<div class="">I’m thinking this indicates that there is some sort
of problem with either the client gateway itself or the network
in between the gateway and the NSD server(s) … thoughts???</div>
<div class=""><br class="">
</div>
<div class="">Thanks in advance…</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">
<div class="">—</div>
<div class="">Kevin Buterbaugh - Senior System Administrator</div>
<div class="">Vanderbilt University - Advanced Computing
Center for Research and Education</div>
<div class=""><a href="mailto:Kevin.Buterbaugh@vanderbilt.edu"
class="" moz-do-not-send="true">Kevin.Buterbaugh@vanderbilt.edu</a> -
(615)875-9633</div>
<div class=""><br class="">
</div>
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<br class="">
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