<html><body><p>The current (V4.2+) levels of code support bigger directory block sizes, so it's no longer an issue with something like 1M metadata block size. In fact, there isn't a whole lot of difference between 256K and 1M metadata block sizes, either would work fine. There isn't really a downside in selecting a different block size for metadata though.<br><br>Inode size (mmcrfs -i option) is orthogonal to the metadata block size selection. We do strongly recommend using 4K inodes to anyone. There's the obvious downside of needing more metadata storage for inodes, but the advantages are significant. <br>yuri<br><br><img width="16" height="16" src="cid:1__=07BB0AA5DFFD9BB18f9e8a93df938690918c07B@" border="0" alt="Inactive hide details for Jan-Frode Myklebust ---09/22/2016 12:25:25 PM---https://www.ibm.com/developerworks/community/forums/h"><font color="#424282">Jan-Frode Myklebust ---09/22/2016 12:25:25 PM---https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-0000147742</font><br><br><font size="2" color="#5F5F5F">From: </font><font size="2">Jan-Frode Myklebust <janfrode@tanso.net></font><br><font size="2" color="#5F5F5F">To: </font><font size="2">gpfsug main discussion list <gpfsug-discuss@spectrumscale.org>, </font><br><font size="2" color="#5F5F5F">Date: </font><font size="2">09/22/2016 12:25 PM</font><br><font size="2" color="#5F5F5F">Subject: </font><font size="2">Re: [gpfsug-discuss] Blocksize</font><br><font size="2" color="#5F5F5F">Sent by: </font><font size="2">gpfsug-discuss-bounces@spectrumscale.org</font><br><hr width="100%" size="2" align="left" noshade style="color:#8091A5; "><br><br><br><a href="https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014774266"><u><font size="4" color="#0000FF">https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014774266</font></u></a><br><br><font size="4">"</font><font size="2" face="Helvetica Neue">Use 256K. Anything smaller makes allocation blocks for the inode file inefficient. Anything larger wastes space for directories. These are the two largest consumers of metadata space." --</font><font size="4">dlmcnabb</font><br><br><font size="2" face="Helvetica Neue">A bit old, but I would assume it still applies.</font><br><br><br><font size="2" face="Helvetica Neue"> -jf</font><br><br><br><font size="4">On Thu, Sep 22, 2016 at 8:36 PM, Stef Coene <</font><a href="mailto:stef.coene@docum.org" target="_blank"><u><font size="4" color="#0000FF">stef.coene@docum.org</font></u></a><font size="4">> wrote:</font><ul><font size="4">Hi,<br><br>Is it needed to specify a different blocksize for the system pool that holds the metadata?<br><br>IBM recommends a 1 MB blocksize for the file system.<br>But I wonder a smaller blocksize (256 KB or so) for metadata is a good idea or not...<br><br><br>Stef<br>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at </font><a href="http://spectrumscale.org/" target="_blank"><u><font size="4" color="#0000FF">spectrumscale.org</font></u></a><u><font size="4" color="#0000FF"><br></font></u><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank"><u><font size="4" color="#0000FF">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</font></u></a></ul><tt>_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org<br></tt><tt><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></tt><tt><br></tt><br><BR>
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