<div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:12pt" ><div dir="ltr" >As you have learned there is no simple formula for setting the maxStatToCache, or for that matter the maxFilesToCache, configuration values. Memory is certainly one consideration but another is directory listing operations. The information kept in the stat cache is sufficient for fulfilling directory listings. If your users are doing directory listings regularly then a larger stat cache could be helpful. </div>
<div dir="ltr" ><div class="socmaildefaultfont" dir="ltr" style="font-family:Arial, Helvetica, sans-serif;font-size:10.5pt" ><div dir="ltr" ><br><font size="2" face="Default Sans Serif,Verdana,Arial,Helvetica,sans-serif" ><span style="font-size:1.143em;" >Fred<br>__________________________________________________<br>Fred Stock | IBM Pittsburgh Lab | 720-430-8821<br>stockf@us.ibm.com</span></font></div></div></div>
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<blockquote data-history-content-modified="1" dir="ltr" style="border-left:solid #aaaaaa 2px; margin-left:5px; padding-left:5px; direction:ltr; margin-right:0px" >----- Original message -----<br>From: Philipp Grau <phgrau@zedat.fu-berlin.de><br>Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>To: gpfsug main discussion list <gpfsug-discuss@spectrumscale.org><br>Cc:<br>Subject: [EXTERNAL] [gpfsug-discuss] maxStatCache and maxFilesToCache: Tip "gpfs_maxstatcache_low".<br>Date: Fri, Mar 13, 2020 8:49 AM<br>
<div><font size="2" face="Default Monospace,Courier New,Courier,monospace" >Hello,<br><br>we have a two node NSD cluster based on a DDN system. Currently we<br>run Spectrum Scale 5.0.4.1 in an HPC environment.<br><br>Mmhealth shows a tip stating "gpfs_maxstatcache_low". Our current settings are:<br><br># mmdiag --config | grep -i cache<br> ! maxFilesToCache 3000000<br> maxStatCache 10000<br><br>maxFilesToCache was tuned during installion and maxStatCache is the<br>according default value.<br><br>After discussing this issue on the german spectumscale meeting, I<br>understand that it is difficult to give a formula on howto calulate<br>this values.<br><br>But I learnt that a FilesToCache entry costs about 10 kbytes of memory<br>and a StatCache entry about 500 bytes. And typically maxStatCache<br>should (obviously) be greater than maxFilesToCache. There is a average<br>100 GB memory usage on our systems (with a total of 265 GB RAM).<br><br>So setting maxStatCache to at least 3000000 should be no problem. But<br>is that correct or to high/low?<br><br>Has anyone some hints or thoughts on this topic? Help is welcome.<br><br>Regards,<br><br>Philipp<br><br>--<br> Philipp Grau | Freie Universitaet Berlin <br> phgrau@ZEDAT.FU-Berlin.DE | Zentraleinrichtung fuer Datenverarbeitung<br> Tel: +49 (30) 838 56583 | Fabeckstr. 32 <br> Fax: +49 (30) 838 56721 | 14195 Berlin <br>_______________________________________________<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> </font><br> </div></blockquote>
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