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-9347 Lustre <p>According to my web searches, the approved way to find out the<br/> needed alignment for the i/o is the result of the BLKSSZGET ioctl:</p> <p> ioctl (fd, BLKSSZGET, &amp;(align))</p> <p>However, on Lustre we get the error:</p> <p> Inappropriate ioctl for device</p> <p>Is this ioctl supported and I'm just doing it wrong?<br/> Or is this ioctl indeed not allowed on Lustre ? And if so,<br/> what is the approved way to find out the alignment ?</p> LU-9347

Getting BLKSSZGET using ioctl

Question/Request Minor Resolved Fixed Emoly Liu Mahmoud Hanafi Fri, 14 Apr 2017 22:01:29 +0000 Thu, 14 Sep 2017 20:46:23 +0000 Thu, 31 Aug 2017 19:35:48 +0000 Lustre 2.7.0 Lustre 2.10.1 Lustre 2.11.0 0 6 <p>Emoly</p> <p>Could you please assist with this one?</p> <p>Thanks</p> <p>Peter</p> <p>Mahmoud, what is the requirement for the alignment? Is this for O_DIRECT on the client, or something else?</p> <p>The I/O will be issued from a client. We want to ensure alignment of IO for max throughput. </p> <p>The optimal IO size for maximum performance is returned via <tt>stat(2)</tt> on the filename or <tt>fstat(2)</tt> on the open file descriptor:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre> blksize_t st_blksize;/* optimal file sys I/O ops blocksize */ </pre> </div></div> <p>For Lustre this is typically 1MB or 2MB. The <tt>BLKSSZGET</tt> ioctl is for returning the minimum alignment for O_DIRECT. For Lustre this is 4096 bytes (<tt>PAGE_SIZE</tt>), though on other filesystems it is typically 512 or 4096 bytes (sector size).</p> <p>Emoly, I think for Lustre it would be possible to return <tt>PAGE_SIZE</tt> from <tt>ll_file_ioctl()</tt> for this call.</p> <p>Emoly Liu (emoly.liu@intel.com) uploaded a new patch: <a href="https://review.whamcloud.com/28578" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/28578</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9347" title="Getting BLKSSZGET using ioctl" class="issue-link" data-issue-key="LU-9347"><del>LU-9347</del></a> ioctl: Add BLKSSZGET ioctl support<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 8db1f7c135b3b482ebb2bacb49a3a1e315b0cf25</p> <p>Hi Emoly, should I consider #28578 patchset #4 good and cherry-pick that one?</p> <p>Jay</p> <p>I would advise holding off until the fix has landed to master if possible - it is still subject to further change until then</p> <p>Peter</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="https://review.whamcloud.com/28578/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/28578/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9347" title="Getting BLKSSZGET using ioctl" class="issue-link" data-issue-key="LU-9347"><del>LU-9347</del></a> ioctl: Add BLKSSZGET ioctl support<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: dcc32cd7d0d89a49f0c73ecf99130a2678442e55</p> <p>Landed for 2.11</p> <p>Minh Diep (minh.diep@intel.com) uploaded a new patch: <a href="https://review.whamcloud.com/28861" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/28861</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9347" title="Getting BLKSSZGET using ioctl" class="issue-link" data-issue-key="LU-9347"><del>LU-9347</del></a> ioctl: Add BLKSSZGET ioctl support<br/> Project: fs/lustre-release<br/> Branch: b2_10<br/> Current Patch Set: 1<br/> Commit: 0f524780288c1a59de0e44c0f839cf7bb0657dde</p> <p>John L. Hammond (john.hammond@intel.com) merged in patch <a href="https://review.whamcloud.com/28861/" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/28861/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-9347" title="Getting BLKSSZGET using ioctl" class="issue-link" data-issue-key="LU-9347"><del>LU-9347</del></a> ioctl: Add BLKSSZGET ioctl support<br/> Project: fs/lustre-release<br/> Branch: b2_10<br/> Current Patch Set: <br/> Commit: 7d89cc84b7f82fe847d481aa70ea38bb345968ed</p> Related Development Rank 1|hzzaav: Rank (Obsolete) 9223372036854775807