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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Lots of details in a presentation I did last year before I left IBM <span style='font-family:Wingdings'>à</span> <a href="http://files.gpfsug.org/presentations/2018/Singapore/Sven_Oehme_ESS_in_CORAL_project_update.pdf">http://files.gpfsug.org/presentations/2018/Singapore/Sven_Oehme_ESS_in_CORAL_project_update.pdf</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Sven<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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 Daniel Kidger <daniel.kidger@uk.ibm.com><br><b>Reply-To: </b>gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br><b>Date: </b>Thursday, March 21, 2019 at 10:15 AM<br><b>To: </b><gpfsug-discuss@spectrumscale.org><br><b>Cc: </b><gpfsug-discuss@spectrumscale.org><br><b>Subject: </b>Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR<o:p></o:p></span></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>Alvise,<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>Also note that that DeveloperWorks page was maintained by Scott Faddon. He has since left IBM and that page has unfortunately not been updated for almost 2 years. :-(<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>This page predates the current version 5.x of SpectrumScale which has been available since the beginning of 2018.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>In version 5.x. the statement that there are <em><span style='font-family:"Arial",sans-serif'>32 sub-blocks in one block</span></em> is no longer true.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>Now, by default you get a 4MiB Filesystem blocksize that has 512 sub0clocks, each 8192 bytes long.<o:p></o:p></span></p></div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div style='margin-top:15.0pt'><div style='margin-top:7.5pt'><div><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif'>Daniel<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Helvetica Neue";color:#19A9F3'>_________________________________________________________</span><span style='font-size:10.5pt;font-family:"Arial",sans-serif'><br></span><b><span style='font-size:10.0pt;font-family:"Arial",sans-serif;color:gray'>Daniel Kidger</span></b><span style='font-size:10.5pt;font-family:"Arial",sans-serif'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial",sans-serif;color:#121212'>IBM Technical Sales Specialist</span><span style='font-size:10.5pt;font-family:"Arial",sans-serif'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial",sans-serif;color:#121212'>Spectrum Scale, Spectrum NAS and IBM Cloud Object Store<br><br></span><span style='font-size:6.5pt;font-family:"Arial",sans-serif;color:#121212'>+</span><span style='font-size:9.0pt;font-family:"Verdana",sans-serif;color:#5F5F5F'>44-(0)7818 522 266 </span><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:#121212'><br></span><span style='font-size:8.0pt;font-family:"Arial",sans-serif;color:#5F5F5F'>daniel.kidger@uk.ibm.com</span><span style='font-size:10.5pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=264 style='width:2.75in;border-collapse:collapse;word-wrap:break-word'><tr><td width=88 style='width:66.0pt;padding:.75pt .75pt .75pt .75pt;overflow:hidden'><p class=MsoNormal><a href="https://www.youracclaim.com/badges/687cf790-fe65-4a92-b129-d23ae41862ac/public_url" target="_blank"><span style='color:windowtext;text-decoration:none'><span style='color:blue;border:solid windowtext 1.0pt;padding:0in'><img border=0 width=32 height=32 style='width:.3333in;height:.3333in' id="_x0000_i1027" src="cid:~WRD000.jpg" alt="Image removed by sender."></span></span></a><o:p></o:p></p></td><td width=88 style='width:66.0pt;padding:.75pt .75pt .75pt .75pt;overflow:hidden'><p class=MsoNormal><a href="https://www.youracclaim.com/badges/8153c6a7-3e02-40be-87ee-24e27ae9459c/public_url" target="_blank"><span style='color:windowtext;text-decoration:none'><span style='color:blue;border:solid windowtext 1.0pt;padding:0in'><img border=0 width=32 height=32 style='width:.3333in;height:.3333in' id="_x0000_i1026" src="cid:~WRD000.jpg" alt="Image removed by sender."></span></span></a><o:p></o:p></p></td><td width=88 style='width:66.0pt;padding:.75pt .75pt .75pt .75pt;overflow:hidden'><p class=MsoNormal><a href="https://www.youracclaim.com/badges/78197e2c-4277-4ec9-808b-ad6abe1e1b16/public_url" target="_blank"><span style='color:windowtext;text-decoration:none'><span style='color:blue;border:solid windowtext 1.0pt;padding:0in'><img border=0 width=32 height=32 style='width:.3333in;height:.3333in' id="_x0000_i1025" src="cid:~WRD000.jpg" alt="Image removed by sender."></span></span></a><o:p></o:p></p></td></tr></table><div><p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div><blockquote style='border:none;border-left:solid #AAAAAA 1.5pt;padding:0in 0in 0in 4.0pt;margin-left:3.75pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>----- Original message -----<br>From: david_johnson@brown.edu<br>Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>To: gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>Cc:<br>Subject: Re: [gpfsug-discuss] Clarification about blocksize in stardanrd gpfs and GNR<br>Date: Thu, Mar 21, 2019 1:32 PM<br> <br>The underlying device in this context is the NSD, network storage device. This has relation at all to 512 byte or 4K disk blocks. Usually around a meg, always a power of two. <br> <o:p></o:p></span></p><div id=AppleMailSignature><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> -- ddj <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>Dave Johnson<o:p></o:p></span></p></div></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'><br>On Mar 21, 2019, at 9:22 AM, Dorigo Alvise (PSI) <<a href="mailto:alvise.dorigo@psi.ch" target="_blank">alvise.dorigo@psi.ch</a>> wrote:<br> <o:p></o:p></span></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>Hi,<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>I'm a little bit puzzled about different meanings of blocksize for different GPFS installation (standard and gnr).<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>From this page <a href="https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/General%20Parallel%20File%20System%20(GPFS)/page/File%20System%20Planning" target="_blank">https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/General%20Parallel%20File%20System%20(GPFS)/page/File%20System%20Planning</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>I read:<o:p></o:p></span></p></div><div><ul type=disc><li class=MsoNormal style='color:black;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>The <b>blocksize</b> is the largest size IO that GPFS can issue to the underlying device</span><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif'><o:p></o:p></span></li><li class=MsoNormal style='color:black;mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 level1 lfo1'><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>A <b>subblock</b> is 1/32nd of blocksize. This is the smallest allocation to a single file</span><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif'><o:p></o:p></span></li></ul><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>For non-gnr GPFS device is quite clear to me (I hope): it is a single spinning disk (or ssd). And I verified this on a small cluster composed of nsd using their local hard drive.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>Can someone explain what is the "device" in the case of GNR ? a single pdisk ?<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'>Thanks,<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> Alvise <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black'> <o:p></o:p></span></p></div></div></div></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'>_______________________________________________<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></span></p></div></blockquote><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Courier New"'>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org<br><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></span><span style='font-size:9.0pt;font-family:"Arial",sans-serif'><o:p></o:p></span></p></div></blockquote><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial",sans-serif'> <o:p></o:p></span></p></div></div><p class=MsoNormal>Unless stated otherwise above:<br>IBM United Kingdom Limited - Registered in England and Wales with number 741598. <br>Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU<br><br>_______________________________________________ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss <o:p></o:p></p></div></body></html>