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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">There certainly *<b>were</b>* issues.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">See for example: <a href="http://files.gpfsug.org/presentations/2018/London/6_GPFSUG_EBI.pdf">
http://files.gpfsug.org/presentations/2018/London/6_GPFSUG_EBI.pdf</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">And the follow on IBM talk on the same day:
<a href="http://files.gpfsug.org/presentations/2018/London/6_MMAP_V2.pdf">http://files.gpfsug.org/presentations/2018/London/6_MMAP_V2.pdf</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">And also from this year:
<a href="https://www.spectrumscaleug.org/event/ssugdigital-spectrum-scale-expert-talks-update-on-performance-enhancements-in-spectrum-scale/">
https://www.spectrumscaleug.org/event/ssugdigital-spectrum-scale-expert-talks-update-on-performance-enhancements-in-spectrum-scale/</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">So it may have been true. If it still is, maybe, but it will depend on your GPFS code.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Simon<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black"><gpfsug-discuss-bounces@spectrumscale.org> on behalf of "Saula, Oluwasijibomi" <oluwasijibomi.saula@ndsu.edu><br>
<b>Reply to: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Date: </b>Tuesday, 22 June 2021 at 16:17<br>
<b>To: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Subject: </b>[gpfsug-discuss] GPFS bad at memory-mapped files?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Hello,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">While reviewing AMS software suite for installation, I noticed this remark (<a href="https://www.scm.com/doc/Installation/Additional_Information_and_Known_Issues.html#gpfs-file-system">https://www.scm.com/doc/Installation/Additional_Information_and_Known_Issues.html#gpfs-file-system</a>):<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">-----<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<h2 style="margin:0cm;background:white;box-sizing:border-box"><span style="font-family:"Georgia",serif;color:#303030">GPFS file system<o:p></o:p></span></h2>
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<span style="font-size:12.0pt;font-family:"Helvetica Neue";color:#303030">Starting with AMS2019, the KF sub-system (used for handling binary files such as ADF’s TAPE* files) has been rewritten to use memory-mapped files. The mmap() system call implementation
is file-system dependent and, unfortunately, it is not equally efficient in different file systems. The memory-mapped files implementation in GPFS is extremely inefficient. Therefore the users should avoid using a GPFS for scratch files<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">--------<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Is this claim true? Are there caveats to this statement, if true?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">Thanks,</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p style="background:white;text-align:start"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">Oluwasijibomi (Siji) Saula</span></b><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">HPC Systems Administrator / Information Technology</span><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"> </span><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black;background:white">Research 2 Building</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"> 220B / Fargo ND 58108-6050</span><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">p: 701.231.7749 / <a href="http://www.ndsu.edu/" target="_blank"><span style="color:purple">www.ndsu.edu</span></a></span><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"> </span><span style="color:#201F1E"><o:p></o:p></span></p>
<p style="background:white;text-align:start"><span style="color:#1F497D"><img border="0" width="32" height="32" style="width:.3333in;height:.3333in" id="_x0000_i1025" src="cid:image001.gif@01D57DE0.91C300C0"></span><span style="color:#201F1E"><o:p></o:p></span></p>
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