<html><body><p><font size="2">In released GPFS, we only support one subblocks-per-fullblock in one file system, like Sven mentioned that the subblocks-per-fullblock is derived by the smallest block size of metadata and data pools, the smallest block size decides the subblocks-per-fullblock and subblock size of all pools. </font><br><br><font size="2">There's an enhancement plan to have pools with different block sizes and/or subblocks-per-fullblock.</font><br><br><font size="2">Thanks,</font><br><font size="2">Yuan, Zheng Cai</font><br><br><img width="16" height="16" src="cid:1__=0ABB084EDFBDBC8E8f9e8a93df938690918c0AB@" border="0" alt="Inactive hide details for "Andrew Beattie" ---2018/08/02 09:10:38---Stephen, Sorry your right, I had to go back and look up w"><font size="2" color="#424282">"Andrew Beattie" ---2018/08/02 09:10:38---Stephen, Sorry your right, I had to go back and look up what we were doing for metadata. but we</font><br><br><font size="2" color="#5F5F5F">From: </font><font size="2">"Andrew Beattie" <abeattie@au1.ibm.com></font><br><font size="2" color="#5F5F5F">To: </font><font size="2">gpfsug-discuss@spectrumscale.org</font><br><font size="2" color="#5F5F5F">Date: </font><font size="2">2018/08/02 09:10</font><br><font size="2" color="#5F5F5F">Subject: </font><font size="2">Re: [gpfsug-discuss] Sub-block size not quite as expected on GPFS 5 filesystem?</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><font face="Arial">Stephen,</font><br><font face="Arial"> </font><br><font face="Arial">Sorry your right, I had to go back and look up what we were doing for metadata.</font><br><font face="Arial"> </font><br><font face="Arial">but we ended up with 1MB block for metadata and 8MB for data and a 32k subblock based on the 1MB metadata block size, effectively a 256k subblock for the Data </font><br><font face="Arial"> </font><br><font face="Arial"> </font><br><b><font color="#7C7C5F">Andrew Beattie</font></b><br><b><font size="2">Software Defined Storage - IT Specialist</font></b><br><b><font size="1" color="#336699">Phone: </font></b><font size="1">614-2133-7927</font><br><b><font size="1" color="#336699">E-mail: </font></b><a href="mailto:abeattie@au1.ibm.com"><u><font size="1" color="#555555">abeattie@au1.ibm.com</font></u></a><br><font face="Arial"> </font><br><font face="Arial"> </font><br><font face="Arial">----- Original message -----<br>From: Stephen Ulmer <ulmer@ulmer.org><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] Sub-block size not quite as expected on GPFS 5 filesystem?<br>Date: Thu, Aug 2, 2018 11:00 AM<br> </font><br><font face="Arial"> </font><br><font face="Arial"> </font><ul><ul><font face="Arial">On Aug 1, 2018, at 8:11 PM, Andrew Beattie <</font><a href="mailto:abeattie@au1.ibm.com" target="_blank"><u><font color="#0000FF" face="Arial">abeattie@au1.ibm.com</font></u></a><font face="Arial">> wrote:</font><br><font face="Arial"> </font></ul></ul><font face="Arial"><br>[…]</font><br><font face="Arial"> </font><ul><ul><font face="Arial"> </font><br><font face="Arial">which is probably why 32k sub block was the default for so many years ....</font></ul></ul><font face="Arial"> </font><br><font face="Arial">I may not be remembering correctly, but I thought the default block size was 256k, and the sub-block size was always fixed at 1/32nd of the block size — which only yields 32k sub-blocks for a 1MB block size. </font><br><font face="Arial"> </font><br><font face="Arial">I also think there used to be something special about a 16k block size… but I haven’t slept well in about a week, so I might just be losing it.</font><br><font face="Arial"> </font><br><font face="Arial">-- <br>Stephen<br> </font><br><tt><font size="2">_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org</font></tt><tt><u><font size="2" color="#0000FF"><br></font></u></tt><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank"><tt><u><font size="2" color="#0000FF">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</font></u></tt></a><br><font face="Arial"> </font><br><tt><font size="2">_______________________________________________<br>gpfsug-discuss mailing list<br>gpfsug-discuss at spectrumscale.org<br></font></tt><tt><font size="2"><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></font></tt><tt><font size="2"><br></font></tt><br><br><BR>
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