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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">You could put all of your data onto SSDs in a RAID1 configuration so that you don’t have insane read-modify-write penalties on writes (RAID1) and avoid horrible
seek thrashing that spinning rust requires (SSD random access medium) for your 4K I/O operations.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">One of my favorite Yuri quotes, “The mmap code is like asbestos… best not to touch it”. He gave many reasons why mmap operations on a distributed file system
is incredibly hard and not recommended.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">-Bryan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> gpfsug-discuss-bounces@spectrumscale.org [mailto:gpfsug-discuss-bounces@spectrumscale.org]
<b>On Behalf Of </b>Sven Oehme<br>
<b>Sent:</b> Friday, January 12, 2018 8:45 AM<br>
<b>To:</b> coetzee.ray@gmail.com; gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>
<b>Subject:</b> Re: [gpfsug-discuss] mmap performance against Spectrum Scale<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<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">what version of Scale are you using right now ?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Fri, Jan 12, 2018 at 2:29 AM Ray Coetzee <<a href="mailto:coetzee.ray@gmail.com">coetzee.ray@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">I'd like to ask the group of their experiences in improving the performance of applications that use mmap calls against files on Spectrum Scale.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Besides using an NFS export from CES instead of a native GPFS mount, or precaching the dataset into the pagepool, what other approaches are there to offset the performance hit of the 4K IO size?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:#888888">Kind regards</span><o:p></o:p></p>
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<p>Ray Coetzee<o:p></o:p></p>
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<p class="MsoNormal">_______________________________________________<br>
gpfsug-discuss mailing list<br>
gpfsug-discuss at <a href="http://spectrumscale.org" target="_blank">spectrumscale.org</a><br>
<a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a><o:p></o:p></p>
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