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-4259 Lustre <p>ZFS mounts do not report the same statistics as reported by ldiskfs. It is impossible to determine IO size, IO rates or other values needed for troubleshooting and performance analysis. </p> LU-4259

No brw_stats on ZFS

Technical task LU-3300 Blocker Resolved Fixed Nathaniel Clark Cliff White prz zfs Fri, 15 Nov 2013 17:30:21 +0000 Wed, 18 Mar 2015 14:57:06 +0000 Mon, 5 Jan 2015 17:45:13 +0000 Lustre 2.6.0 Lustre 2.7.0 Lustre 2.7.0 0 10 <p>You maybe able to use block level tool like "iostat" to get at some of the information easily. </p> <p>No, iostat does not give the timing information offered by brw_stat, neither is it aware of Lustre IO. </p> <p>Io stat will tell you all sorts of timing information . </p> <p>Many of the disk brw_stats might be available on an aggregate basis, if the plumbing is available in ZFS. The per-client and per-job brw_stats is much more tricky because the ZFS IO is not allocated or submitted to disk until long after the service thread has completed processing the request.</p> <p>The RPC information like "pages per bulk r/w" and "discontiguous pages" could be available independent of the OSD type. These should really be OFD statistics, maybe in a new "rpc_stats" file, possibly in YAML format? These could also be available on a per-client or per-request basis. This might be enough for your debugging purposes?</p> <p>Information like "disk I/Os in flight", "I/O time", and "disk I/O size" might be gotten at an aggregate basis from ZFS. The "discontiguous blocks" and "disk fragmented I/Os" would be much harder to collect for writes, without deep hooks into the ZFS IO scheduler. Some of this information could be extracted for reads, by hacking into the ZFS block pointers to get the physical disk blocks.</p> <p>Nathaniel is looking into this</p> <p><a href="http://review.whamcloud.com/11467" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/11467</a></p> <p>Patch has been rebased to latest master. Please review.</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/11467/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/11467/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-4259" title="No brw_stats on ZFS" class="issue-link" data-issue-key="LU-4259"><del>LU-4259</del></a> osd-zfs: Add brw_stats collection and display<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: efdacb72afa55fc8b5ad155c479aa34ef0af118a</p> Related LU-2261 LU-3300 Development Rank 1|hzw91b: Rank (Obsolete) 11623