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-13012 Lustre <p>In current WBC prototype,  all newly directories are created with subtree EX lock returned (WBC). All directories are treated equally with metadata writeback caching. There is no any customization.</p> <p>It can define various auto caching rule for WBC when create a new directory similar to TBF or PCC.</p> <p>When a new create directory meets the rule condition, it can try to obtain EX WBC lock from MDS and keep exclusive access on the directory under the protection of the EX lock on the client.</p> <p>The rule can be combination of uid/gid/projid/fname or jobid.</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java"> # lctl wbc $MOUNT $rule # lctl wbc /mnt/lustre “projid={100}” # lctl wbc /mnt/lustre “uid={500}&amp;gid={500},fname={*dirmatch*}” # lctl wbc /mnt/lustre “jobid={dd.*}” </pre> </div></div> LU-13012

WBC: Rule based auto WBC

Technical task LU-10938 Minor Open Unresolved Qian Yingjin Qian Yingjin Tue, 26 Nov 2019 09:41:52 +0000 Tue, 17 May 2022 07:54:35 +0000 0 3 <p>I suspect that in most cases this should not be needed. Caching metadata does not take a lot of space compared to file data, and if the background age and lock cancellation is working efficiently then WBC should be totally transparent to the user. The main use for this would be to allow tuning the WBC state of existing directories if a simple policy like "ask MDS for EX lock after N creates in existing directory" is not enough. The MDS can always refuse the EX lock and just create the file if there is contention in that directory. </p> <p>This should be considered a WBC v2 "nice to have" goal, but I don't think it is needed for v1. It would probably make more sense to spend time to optimize the writeback performance (eg. batch RPCs) so that cache flush can happen quickly and efficiently in the background.</p> <p>"Yingjin Qian &lt;qian@ddn.com&gt;" uploaded a new patch: <a href="https://review.whamcloud.com/47312" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/47312</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-13012" title="WBC: Rule based auto WBC" class="issue-link" data-issue-key="LU-13012">LU-13012</a> wbc: auto WBC based on the rule of project ID<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 8c18008e01c2636bcd801af945d436394cc7097e</p> <p>"Yingjin Qian &lt;qian@ddn.com&gt;" uploaded a new patch: <a href="https://review.whamcloud.com/47338" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/47338</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-13012" title="WBC: Rule based auto WBC" class="issue-link" data-issue-key="LU-13012">LU-13012</a> pcc: abstract rule parsing and matching func<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: be131170885253952332d7f8083f3e4247fd5354</p> <p>"Yingjin Qian &lt;qian@ddn.com&gt;" uploaded a new patch: <a href="https://review.whamcloud.com/47367" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/47367</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-13012" title="WBC: Rule based auto WBC" class="issue-link" data-issue-key="LU-13012">LU-13012</a> wbc: customizable rule based auto WBC<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 2968194daf58c4dbe6e5361dbde33a381e4c986c</p> Related LU-10938 LU-13015 Development Rank 1|i00pxr: Rank (Obsolete) 9223372036854775807