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-9161 Lustre <p>The <tt>meta_bg</tt> feature unfortunately fragments the group descriptor block across the whole filesystem, rather than continuously at the start of the device. This causes a large amount of seeking (at least 32768 seeks for a 256TB filesystem). </p> <p>Skipping the loading of inode tables and bitmaps via <tt>-c</tt> will avoid reading many GB of data. </p> LU-9161

mount_utils_ldiskfs.c is_feature_enabled() should pass '-c' to debugfs

Bug Minor Resolved Fixed WC Triage John Hammond easy Mon, 27 Feb 2017 17:33:19 +0000 Tue, 14 Mar 2017 06:10:53 +0000 Tue, 14 Mar 2017 06:10:53 +0000 Lustre 2.10.0 0 3 <p>Instead of running <tt>debugfs</tt> in a shell and parsing the text output, we might consider just reading <tt>struct ext4_super_block</tt> at offset 1024 bytes, and then checking the binary feature flags directly. That will avoid all overhead from reading the group descriptors and any other metadata. Another alternative is to modify debugfs to avoid loading the bitmaps until required (possibly only starting a background prefetch at filesystem open time) as an extension of the <a href="https://jira.whamcloud.com/browse/LU-9160" title="Very slow mount of 300TB+ ldiskfs volume" class="issue-link" data-issue-key="LU-9160"><del>LU-9160</del></a> patch.</p> <p>Andreas Dilger (andreas.dilger@intel.com) uploaded a new patch: <a href="https://review.whamcloud.com/25671" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/25671</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9161" title="mount_utils_ldiskfs.c is_feature_enabled() should pass &#39;-c&#39; to debugfs" class="issue-link" data-issue-key="LU-9161"><del>LU-9161</del></a> utils: don't load bitmaps when checking features<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: e9d8b14e3f893b1e82561b47c84b2000e7e2c2c3</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="https://review.whamcloud.com/25671/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/25671/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9161" title="mount_utils_ldiskfs.c is_feature_enabled() should pass &#39;-c&#39; to debugfs" class="issue-link" data-issue-key="LU-9161"><del>LU-9161</del></a> utils: don't load bitmaps when checking features<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 153c25f280d3db722005619ea0db6fbd3d26bc97</p> <p>Landed for 2.10</p> Related LU-9160 Development Rank 1|hzz57r: Rank (Obsolete) 9223372036854775807 Severity