<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">This presentation contains lots of good information about file system structure in general, and GPFS in specific, and I appreciate that and enjoyed reading it.</div><div class=""><br class=""></div>However, it states outright (both graphically and in text) that storage pools are a feature of the cluster, not of a file system — which I believe to be completely incorrect. For example, it states that there is "only one system pool per cluster", rather than one per file system.<div class=""><br class=""></div><div class="">Given that this was written by IBMers and presented at an actual users’ group, can someone please weigh in on this? I’m asking because it represents a fundamental misunderstanding of a very basic GPFS concept, which makes me wonder how authoritative the rest of it is...</div><div class=""><div class=""><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">-- <br class="">Stephen<br class=""><br class=""><br class=""></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Mar 26, 2019, at 12:27 PM, Dorigo Alvise (PSI) <<a href="mailto:alvise.dorigo@psi.ch" class="">alvise.dorigo@psi.ch</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div style="caret-color: rgb(0, 0, 0); font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; direction: ltr; font-family: Tahoma; font-size: 10pt;" class=""><div class="">Hi Marc,<br class=""></div><div class="">"Indirect block size" is well explained in this presentation:<span class="Apple-converted-space"> </span><br class=""></div><div class=""><br class=""></div><div class=""><a href="http://files.gpfsug.org/presentations/2016/south-bank/D2_P2_A_spectrum_scale_metadata_dark_V2a.pdf" target="_blank" class="">http://files.gpfsug.org/presentations/2016/south-bank/D2_P2_A_spectrum_scale_metadata_dark_V2a.pdf</a></div><div class=""><br class=""></div><div class="">pages 37-41<br class=""></div><div class=""><br class=""></div><div class="">Cheers,</div><div class=""><br class=""></div><div class=""> Alvise<br class=""></div><div class=""><br class=""></div><div style="font-family: "Times New Roman"; font-size: 16px;" class=""><hr tabindex="-1" class=""><div id="divRpF933280" style="direction: ltr;" class=""><font size="2" face="Tahoma" class=""><b class="">From:</b><span class="Apple-converted-space"> </span><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="">gpfsug-discuss-bounces@spectrumscale.org</a><span class="Apple-converted-space"> </span>[<a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="">gpfsug-discuss-bounces@spectrumscale.org</a>] on behalf of Caubet Serrabou Marc (PSI) [<a href="mailto:marc.caubet@psi.ch" class="">marc.caubet@psi.ch</a>]<br class=""><b class="">Sent:</b><span class="Apple-converted-space"> </span>Tuesday, March 26, 2019 4:39 PM<br class=""><b class="">To:</b><span class="Apple-converted-space"> </span>gpfsug main discussion list<br class=""><b class="">Subject:</b><span class="Apple-converted-space"> </span>[gpfsug-discuss] GPFS v5: Blocksizes and subblocks<br class=""></font><br class=""></div><div class=""></div><div class=""><div style="direction: ltr; font-family: Tahoma; font-size: 10pt;" class=""><div class="">Hi all,</div><div class=""><br class=""></div><div class="">according to several GPFS presentations as well as according to the man pages:</div><div class=""><br class=""></div><div class=""><font face="Courier New" class=""> Table 1. Block sizes and subblock sizes<br class=""><br class="">+-------------------------------+-------------------------------+<br class="">| Block size | Subblock size |<br class="">+-------------------------------+-------------------------------+<br class="">| 64 KiB | 2 KiB |<br class="">+-------------------------------+-------------------------------+<br class="">| 128 KiB | 4 KiB |<br class="">+-------------------------------+-------------------------------+<br class="">| 256 KiB, 512 KiB, 1 MiB, 2 | 8 KiB |<br class="">| MiB, 4 MiB | |<br class="">+-------------------------------+-------------------------------+<br class="">| 8 MiB, 16 MiB | 16 KiB |<br class="">+-------------------------------+-------------------------------+</font><br class=""><br class=""></div><div class="">A block size of 8MiB or 16MiB should contain subblocks of 16KiB.</div><div class=""><br class=""></div><div class="">However, when creating a new filesystem with 16MiB blocksize, looks like is using 128KiB subblocks:</div><div class=""><br class=""></div><div class=""><font face="Courier New" class="">[root@merlindssio01 ~]# mmlsfs merlin<br class="">flag value description<br class="">------------------- ------------------------ -----------------------------------<br class=""> -f 8192 Minimum fragment (subblock) size in bytes (system pool)<br class=""> 131072 Minimum fragment (subblock) size in bytes (other pools)<br class=""> -i 4096 Inode size in bytes<br class=""> -I 32768 Indirect block size in bytes<br class="">.</font></div><div class=""><font face="Courier New" class="">.</font></div><div class=""><font face="Courier New" class="">.<br class=""></font></div><div class=""><font face="Courier New" class=""> -n 128 Estimated number of nodes that will mount file system<br class=""> -B 1048576 Block size (system pool)<br class=""> 16777216 Block size (other pools)<br class="">.</font></div><div class=""><font face="Courier New" class="">.</font></div><div class=""><font face="Courier New" class="">.</font><br class=""></div><div class=""><br class=""></div><div class="">What am I missing? According to documentation, I expect this to be a fixed value, or it isn't at all?<br class=""></div><div class=""><br class=""></div><div class="">On the other hand, I don't really understand the concept 'Indirect block size in bytes', can somebody clarify or provide some details about this setting?</div><div class=""><br class=""></div><div class="">Thanks a lot and best regards,</div><div class="">Marc <span class="Apple-converted-space"> </span><br class=""><div style="font-family: Tahoma; font-size: 13px;" class=""><div style="font-family: Tahoma; font-size: 13px;" class=""><div class="BodyFragment"><font size="2" class=""><span style="font-size: 10pt;" class=""><div class="PlainText">_________________________________________<br class="">Paul Scherrer Institut<span class="Apple-converted-space"> </span><br class="">High Performance Computing<br class="">Marc Caubet Serrabou<br class="">Building/Room: WHGA/019A</div><div class="PlainText"><font size="2" class=""><span style="font-size: 10pt;" class="">Forschungsstrasse, 111</span></font></div><div class="PlainText">5232 Villigen PSI<br class="">Switzerland<br class=""><br class="">Telephone: +41 56 310 46 67<br class="">E-Mail:<span class="Apple-converted-space"> </span><a href="mailto:marc.caubet@psi.ch" class="">marc.caubet@psi.ch</a></div></span></font></div></div></div></div></div></div></div></div><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">_______________________________________________</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">gpfsug-discuss mailing list</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">gpfsug-discuss at<span class="Apple-converted-space"> </span></span><a href="http://spectrumscale.org/" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">spectrumscale.org</a><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></div></blockquote></div><br class=""></div></div></body></html>