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<p class="MsoNormal">Thankfully all application developers completely understand why listing directories are a bad idea… ;o)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Or at least they will learn the hard way otherwise,<o:p></o:p></p>
<p class="MsoNormal">-B<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> gpfsug-discuss-bounces@spectrumscale.org <gpfsug-discuss-bounces@spectrumscale.org>
<b>On Behalf Of </b>Marc A Kaplan<br>
<b>Sent:</b> Thursday, August 23, 2018 12:01 PM<br>
<b>To:</b> gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>
<b>Subject:</b> Re: [gpfsug-discuss] Those users.... millions of files per directory - not necessarily a mistake<o:p></o:p></p>
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<p class="MsoNormal"><em><span style="font-size:8.5pt;font-family:"Verdana",sans-serif;color:#333333">Note: External Email</span></em><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">Even with nfs or samba export you're probably okay as long as the application does not attempt to list the directory. Just probe it with stat/open/create/unlink. <br>
</span><br>
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<span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#5F5F5F">From: </span><span style="font-size:9.0pt;font-family:"Arial",sans-serif"><a href="mailto:david_johnson@brown.edu">david_johnson@brown.edu</a></span><br>
<span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#5F5F5F">To: </span><span style="font-size:9.0pt;font-family:"Arial",sans-serif">gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org">gpfsug-discuss@spectrumscale.org</a>></span><br>
<span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#5F5F5F">Date: </span><span style="font-size:9.0pt;font-family:"Arial",sans-serif">08/23/2018 11:34 AM</span><br>
<span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#5F5F5F">Subject: </span><span style="font-size:9.0pt;font-family:"Arial",sans-serif">Re: [gpfsug-discuss] Those users.... millions of files per directory - not necessarily a mistake</span><br>
<span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#5F5F5F">Sent by: </span><span style="font-size:9.0pt;font-family:"Arial",sans-serif"><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org">gpfsug-discuss-bounces@spectrumscale.org</a></span><o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
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<span style="font-size:12.0pt">But heaven help you if you export the gpfs on nfs or cifs.
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<span style="font-size:12.0pt"> -- ddj</span><br>
<span style="font-size:12.0pt">Dave Johnson</span><br>
<span style="font-size:12.0pt"><br>
On Aug 23, 2018, at 11:23 AM, Marc A Kaplan <</span><a href="mailto:makaplan@us.ibm.com"><span style="font-size:12.0pt">makaplan@us.ibm.com</span></a><span style="font-size:12.0pt">> wrote:<br>
</span><br>
<span style="font-size:10.0pt;font-family:"Arial",sans-serif">Millions of files per directory, may well be a mistake...
<br>
<br>
BUT there are some very smart use cases that might take advantage of GPFS having good performance with large directories --<br>
because GPFS uses extensible hashing -- it is better to store millions of files in a single GPFS directory than artificially scatter them among directories based on the mistaken notion that large directories are bad. (Yeah, they are in most implementations,
but not in GPFS.)</span><span style="font-size:12.0pt"><br>
</span><br>
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