https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-10278 Lustre <p>In order to avoid cache thrashing, lfs migrate currently uses direct i/o to copy file contents, which may leads to significantly different performance compared to normal (non-O_DIRECT) i/o, cf. for example the discussion at <a href="http://lists.lustre.org/pipermail/lustre-discuss-lustre.org/2017-November/015112.html" class="external-link" target="_blank" rel="nofollow noopener">http://lists.lustre.org/pipermail/lustre-discuss-lustre.org/2017-November/015112.html</a>. Internally, we've measured even more extreme differences where O_DIRECT throughput performed at 1/10th the normal rate. Therefore, I'd suggest to leave the choice between normal and direct i/o to the caller of lfs migrate by adding a new option <del>N/</del>-non-direct that suppresses to O_DIRECT flag in the open() call of the source file. Patch to follow.</p> LU-10278

lfs migrate: make use of direct i/o optional

Improvement Minor Resolved Fixed Emoly Liu Daniel Kobras patch Fri, 24 Nov 2017 17:59:39 +0000 Wed, 2 Jan 2019 20:48:12 +0000 Thu, 22 Feb 2018 13:22:00 +0000 Lustre 2.11.0 0 5 <p>Then the correct direction to go is to use AIO+DirectIO. Please take a look at <a href="https://jira.whamcloud.com/browse/LU-4198" title="Improve IO performance when using DIRECT IO using libaio" class="issue-link" data-issue-key="LU-4198"><del>LU-4198</del></a> for enabling AIO in Lustre.</p> <p>I think it is reasonable to have a simple change like this, since the fix to AIO in the kernel is fairly complex (and late for 2.11). The patch to <tt>lfs migrate</tt> should be simple enough that it can be backported to 2.10.x as well.</p> <p>I'm not against making AIO and <tt>copyfile()</tt> work well, but it shouldn't be an obstacle for a small fix in the meantime. </p> <p>Daniel Kobras (d.kobras@science-computing.de) uploaded a new patch: <a href="https://review.whamcloud.com/30301" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/30301</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-10278" title="lfs migrate: make use of direct i/o optional" class="issue-link" data-issue-key="LU-10278"><del>LU-10278</del></a> utils: allow to migrate without direct io<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: b7fde24507db1e007da3c96aaeeadd3f572bff6b</p> <p><a href="https://jira.whamcloud.com/secure/ViewProfile.jspa?name=kobras" class="user-hover" rel="kobras">kobras</a> will you be able to refresh the patch as required?</p> <p>Emoly</p> <p>It seems that <a href="https://jira.whamcloud.com/secure/ViewProfile.jspa?name=kobras" class="user-hover" rel="kobras">kobras</a> is not available to refresh his patch. Could you please assist with this so that we can include this change in 2.11?</p> <p>Thanks</p> <p>Peter</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="https://review.whamcloud.com/30301/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/30301/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-10278" title="lfs migrate: make use of direct i/o optional" class="issue-link" data-issue-key="LU-10278"><del>LU-10278</del></a> utils: allow to migrate without direct io<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: adfb154348c742b073a2b8120f2a9bf4c67fb7fa</p> <p>Landed for 2.11</p> Related LU-4198 LU-11621 Development Rank 1|hzzo8n: Rank (Obsolete) 9223372036854775807