<div dir="ltr"><div><div><div>Kevin,<br><br></div>The math currently used in the code
appears to be "greater than 31 NSD's in the filesystem" combined with
"greater than 31 pit worker
threads", explicitly for a balancing restripe (we actually hit that
combo on an older version of 3.5.x before
the safety got written in there...it was a long day). At least, that's the apparent math used through 4.1.1.10, which we're currently running.<br><br></div>If
pitWorkerThreadsPerNode is set to 0 (default), GPFS should set the active thread number equal to the number of cores in the node, to a max
of 16 threads I believe. Take in mind that for a restripe, it will also
include the threads available on the fs manager.<br><br>So if your fs
manager and at
least one helper node are both set to "0", and each contains at least 16
cores, the
restripe "thread calculation" will exceed 31 threads so it won't run.
We've had to tune our helper nodes to lower numbers (e.g a single helper
node to 15 threads).</div><div><br></div><div>Aaron please correct me if I'm braining that wrong anywhere.<br></div><div><br></div>-Jordan</div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, May 4, 2017 at 12:07 PM, Buterbaugh, Kevin L <span dir="ltr"><<a href="mailto:Kevin.Buterbaugh@vanderbilt.edu" target="_blank">Kevin.Buterbaugh@vanderbilt.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">
Hi Olaf,
<div><br>
</div>
<div>I didn’t touch pitWorkerThreadsPerNode … it was already zero.</div>
<div><br>
</div>
<div>I’m running 4.2.2.3 on my GPFS servers (some clients are on 4.2.1.1 or 4.2.0.3 and are gradually being upgraded). What version of GPFS fixes this? With what I’m doing I need the ability to run mmrestripefs.</div>
<div><br>
</div>
<div>It seems to me that mmrestripefs could check whether QOS is enabled … granted, it would have no way of knowing whether the values used actually are reasonable or not … but if QOS is enabled then “trust” it to not overrun the system.</div>
<div><br>
</div>
<div>PMR time? Thanks..</div><span class="HOEnZb"><font color="#888888">
<div><br>
</div>
<div>Kevin</div></font></span><div><div class="h5">
<div><br>
<div>
<blockquote type="cite">
<div>On May 4, 2017, at 10:54 AM, Olaf Weiser <<a href="mailto:olaf.weiser@de.ibm.com" target="_blank">olaf.weiser@de.ibm.com</a>> wrote:</div>
<br class="m_-5375364777437986490Apple-interchange-newline">
<div><font size="2" face="sans-serif">HI Kevin, </font><br>
<font size="2" face="sans-serif">the number of NSDs is more or less nonsense .. it is just the number of nodes x PITWorker should not exceed to much the #mutex/FS block</font><br>
<font size="2" face="sans-serif">did you adjust/tune the PitWorker ? ...
</font><br>
<br>
<font size="2" face="sans-serif">so far as I know.. that the code checks the number of NSDs is already considered as a defect and will be fixed / is already fixed ( I stepped into it here as well)
</font><br>
<br>
<font size="2" face="sans-serif">ps. QOS is the better approach to address this, but unfortunately.. not everyone is using it by default... that's why I suspect , the development decide to put in a check/limit here .. which in your case(with QOS) would'nt
needed </font><br>
<br>
<br>
<br>
<br>
<br>
<font size="1" color="#5f5f5f" face="sans-serif">From: </font><font size="1" face="sans-serif">"Buterbaugh, Kevin L" <<a href="mailto:Kevin.Buterbaugh@Vanderbilt.Edu" target="_blank">Kevin.Buterbaugh@Vanderbilt.<wbr>Edu</a>></font><br>
<font size="1" color="#5f5f5f" face="sans-serif">To: </font><font size="1" face="sans-serif">gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" target="_blank">gpfsug-discuss@spectrumscale.<wbr>org</a>></font><br>
<font size="1" color="#5f5f5f" face="sans-serif">Date: </font><font size="1" face="sans-serif">05/04/2017 05:44 PM</font><br>
<font size="1" color="#5f5f5f" face="sans-serif">Subject: </font><font size="1" face="sans-serif">Re: [gpfsug-discuss] Well, this is the pits...</font><br>
<font size="1" color="#5f5f5f" face="sans-serif">Sent by: </font><font size="1" face="sans-serif"><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" target="_blank">gpfsug-discuss-bounces@<wbr>spectrumscale.org</a></font><br>
<hr noshade>
<br>
<br>
<br>
<font size="3">Hi Olaf, </font><br>
<br>
<font size="3">Your explanation mostly makes sense, but...</font><br>
<br>
<font size="3">Failed with 4 nodes … failed with 2 nodes … not gonna try with 1 node. And this filesystem only has 32 disks, which I would imagine is not an especially large number compared to what some people reading this e-mail have in their filesystems.</font><br>
<br>
<font size="3">I thought that QOS (which I’m using) was what would keep an mmrestripefs from overrunning the system … QOS has worked extremely well for us - it’s one of my favorite additions to GPFS.</font><br>
<br>
<font size="3">Kevin</font><br>
<br>
<font size="3">On May 4, 2017, at 10:34 AM, Olaf Weiser <</font><a href="mailto:olaf.weiser@de.ibm.com" target="_blank"><font size="3" color="blue"><u>olaf.weiser@de.ibm.com</u></font></a><font size="3">> wrote:</font><br>
<br>
<font size="2" face="sans-serif">no.. it is just in the code, because we have to avoid to run out of mutexs / block</font><font size="3"><br>
</font><font size="2" face="sans-serif"><br>
reduce the number of nodes -N down to 4 (2nodes is even more safer) ... is the easiest way to solve it for now....</font><font size="3"><br>
</font><font size="2" face="sans-serif"><br>
I've been told the real root cause will be fixed in one of the next ptfs .. within this year ..
</font><br>
<font size="2" face="sans-serif">this warning messages itself should appear every time.. but unfortunately someone coded, that it depends on the number of disks (NSDs).. that's why I suspect you did'nt see it before<br>
but the fact , that we have to make sure, not to overrun the system by mmrestripe remains.. to please lower the -N number of nodes to 4 or better 2
</font><font size="3"><br>
</font><font size="2" face="sans-serif"><br>
(even though we know.. than the mmrestripe will take longer)</font><font size="3"><br>
<br>
</font><font size="1" color="#5f5f5f" face="sans-serif"><br>
From: </font><font size="1" face="sans-serif">"Buterbaugh, Kevin L" <</font><a href="mailto:Kevin.Buterbaugh@Vanderbilt.Edu" target="_blank"><font size="1" color="blue" face="sans-serif"><u>Kevin.Buterbaugh@Vanderbilt.<wbr>Edu</u></font></a><font size="1" face="sans-serif">></font><font size="1" color="#5f5f5f" face="sans-serif"><br>
To: </font><font size="1" face="sans-serif">gpfsug main discussion list <</font><a href="mailto:gpfsug-discuss@spectrumscale.org" target="_blank"><font size="1" color="blue" face="sans-serif"><u>gpfsug-discuss@spectrumscale.<wbr>org</u></font></a><font size="1" face="sans-serif">></font><font size="1" color="#5f5f5f" face="sans-serif"><br>
Date: </font><font size="1" face="sans-serif">05/04/2017 05:26 PM</font><font size="1" color="#5f5f5f" face="sans-serif"><br>
Subject: </font><font size="1" face="sans-serif">[gpfsug-discuss] Well, this is the pits...</font><font size="1" color="#5f5f5f" face="sans-serif"><br>
Sent by: </font><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" target="_blank"><font size="1" color="blue" face="sans-serif"><u>gpfsug-discuss-bounces@<wbr>spectrumscale.org</u></font></a><font size="3"><br>
</font>
<hr noshade>
<font size="3"><br>
<br>
<br>
Hi All, <br>
<br>
Another one of those, “I can open a PMR if I need to” type questions…<br>
<br>
We are in the process of combining two large GPFS filesystems into one new filesystem (for various reasons I won’t get into here). Therefore, I’m doing a lot of mmrestripe’s, mmdeldisk’s, and mmadddisk’s.<br>
<br>
Yesterday I did an “mmrestripefs <old fs> -r -N <my 8 NSD servers>” (after suspending a disk, of course). Worked like it should.<br>
<br>
Today I did a “mmrestripefs <new fs> -b -P capacity -N <those same 8 NSD servers>” and got:<br>
<br>
mmrestripefs: The total number of PIT worker threads of all participating nodes has been exceeded to safely restripe the file system. The total number of PIT worker threads, which is the sum of pitWorkerThreadsPerNode of the participating nodes, cannot exceed
31. Reissue the command with a smaller set of participating nodes (-N option) and/or lower the pitWorkerThreadsPerNode configure setting. By default the file system manager node is counted as a participating node.<br>
mmrestripefs: Command failed. Examine previous error messages to determine cause.<br>
<br>
So there must be some difference in how the “-r” and “-b” options calculate the number of PIT worker threads. I did an “mmfsadm dump all | grep pitWorkerThreadsPerNode” on all 8 NSD servers and the filesystem manager node … they all say the same thing:<br>
<br>
pitWorkerThreadsPerNode 0<br>
<br>
Hmmm, so 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 > 31?!? I’m confused...<br>
<br>
—<br>
Kevin Buterbaugh - Senior System Administrator<br>
Vanderbilt University - Advanced Computing Center for Research and Education</font><font size="3" color="blue"><u><br>
</u></font><a href="mailto:Kevin.Buterbaugh@vanderbilt.edu" target="_blank"><font size="3" color="blue"><u>Kevin.Buterbaugh@vanderbilt.<wbr>edu</u></font></a><font size="3">- <a href="tel:(615)%20875-9633" value="+16158759633" target="_blank">(615)875-9633</a><br>
<br>
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