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<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff">Hi,</font></span></div>
<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff"></font></span> </div>
<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff">lfs_migrate will rebalance space usage across the OSTs of your filesystem by copying files and deleting the original ones on the most empty OSTs. It will not change
stripe count of files. You have to migrate lots of files to see the new balance. This is why you don't see the usefulness with only one file.</font></span></div>
<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff">lfs_migrate also accepts options to specify which OSTs you want to redistribute.</font></span></div>
<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff"></font></span> </div>
<div dir="ltr" align="left"><span class="630492012-18072011"><font face="Arial" color="#0000ff">Sebastien.</font></span></div>
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<font face="Tahoma" size="2"><b>From:</b> lustre-discuss-bounces@lists.lustre.org [mailto:lustre-discuss-bounces@lists.lustre.org]
<b>On Behalf Of </b>Andrus, Brian Contractor<br>
<b>Sent:</b> samedi 16 juillet 2011 18:31<br>
<b>To:</b> lustre-discuss@lists.lustre.org<br>
<b>Subject:</b> [Lustre-discuss] lfs_migrate for rebalancing<br>
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<p class="MsoNormal">All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Am I incorrect in the way I read that lfs_migrate can be used to rebalance a filesystem after adding OSTs?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here is some output on a 22M file that was all on one OST and we now have 9:<o:p></o:p></p>
<div style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0in; BORDER-TOP: medium none; PADDING-LEFT: 0in; PADDING-BOTTOM: 1pt; BORDER-LEFT: medium none; PADDING-TOP: 0in; BORDER-BOTTOM: windowtext 2.25pt double; mso-element: para-border-div">
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<o:p> </o:p></p>
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<p class="MsoNormal">[root@compute-3-1 ps2]# lfs getstripe PS01-071.xml<o:p></o:p></p>
<p class="MsoNormal">PS01-071.xml<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_count: 1<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_size: 1048576<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_offset: 6<o:p></o:p></p>
<p class="MsoNormal"> obdidx objid objid group<o:p></o:p></p>
<p class="MsoNormal"> 6 4411098 0x434eda 0<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[root@compute-3-1 ps2]# lfs_migrate -y PS01-071.xml<o:p></o:p></p>
<p class="MsoNormal">PS01-071.xml: done<o:p></o:p></p>
<p class="MsoNormal">[root@compute-3-1 ps2]# lfs getstripe PS01-071.xml<o:p></o:p></p>
<p class="MsoNormal">PS01-071.xml<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_count: 1<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_size: 1048576<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_offset: 4<o:p></o:p></p>
<p class="MsoNormal"> obdidx objid objid group<o:p></o:p></p>
<p class="MsoNormal"> 4 50856625 0x30802b1 0<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[root@compute-3-1 ps2]# cp PS01-071.xml PS01-071.xml.tmp<o:p></o:p></p>
<p class="MsoNormal">[root@compute-3-1 ps2]# lfs getstripe PS01-071.xml.tmp<o:p></o:p></p>
<p class="MsoNormal">PS01-071.xml.tmp<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_count: 9<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_size: 1048576<o:p></o:p></p>
<p class="MsoNormal">lmm_stripe_offset: 2<o:p></o:p></p>
<p class="MsoNormal"> obdidx objid objid group<o:p></o:p></p>
<p class="MsoNormal"> 2 73524719 0x461e5ef 0<o:p></o:p></p>
<p class="MsoNormal"> 5 4389362 0x42f9f2 0<o:p></o:p></p>
<p class="MsoNormal"> 3 53566843 0x3315d7b 0<o:p></o:p></p>
<p class="MsoNormal"> 0 47139754 0x2cf4baa 0<o:p></o:p></p>
<p class="MsoNormal"> 6 4411100 0x434edc 0<o:p></o:p></p>
<p class="MsoNormal"> 1 56746451 0x361e1d3 0<o:p></o:p></p>
<p class="MsoNormal"> 8 4416089 0x436259 0<o:p></o:p></p>
<p class="MsoNormal"> 7 4411127 0x434ef7 0<o:p></o:p></p>
<p class="MsoNormal"> 4 50856626 0x30802b2 0<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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[root@compute-3-1 ps2]#<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So it moved the file to another OST, but left the strip count as 1.<o:p></o:p></p>
<p class="MsoNormal">But when I cp’ed the file, it properly striped it across all the OSTs.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This doesn’t seem all that useful for rebalancing.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="COLOR: #1f497d">Brian Andrus<o:p></o:p></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d">ITACS/Research Computing<o:p></o:p></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d">Naval Postgraduate School<o:p></o:p></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d">Monterey, California<o:p></o:p></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d">voice: 831-656-6238<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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