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-11471 Lustre <p>one of our customer is noticed IO errors during failover with fewer OST. we would like to add a note into the Best practice section or OST planning section <br/> ========================<br/> During Fail over situation with few OSTs possibly cause I/O errors on the client side. </p> Lustre 2.5.X <br/> LU-11471

IO Errors during failover with very few number of OSTs

Bug Minor Closed Duplicate Mikhail Pershin Rajeshwaran Ganesan Thu, 24 Dec 2015 16:09:56 +0000 Sun, 16 Jan 2022 08:27:00 +0000 Sun, 16 Jan 2022 08:27:00 +0000 0 4 <p>we would like add, If the MDS has no currently active OSTs, create requests fail with an I/O error. And we will see the IO errors at the clients.</p> <p>Hi Rajeshwaran,</p> <p>Are you familiar with how to push such an update to the manual?</p> <p>For details on how to submit changes to the manual, please see:</p> <ul class="alternate" type="square"> <li><a href="https://wiki.hpdd.intel.com/display/PUB/Making+changes+to+the+Lustre+Manual" class="external-link" target="_blank" rel="nofollow noopener">https://wiki.hpdd.intel.com/display/PUB/Making+changes+to+the+Lustre+Manual</a></li> <li><a href="https://wiki.hpdd.intel.com/display/PUB/Code+Documentation+Guidelines" class="external-link" target="_blank" rel="nofollow noopener">https://wiki.hpdd.intel.com/display/PUB/Code+Documentation+Guidelines</a></li> </ul> <p>I wonder whether this should rather be considered a bug in the code, and the MDS should block file creations if all of the OSTs become unavailable after startup?</p> <p>please close this case</p> <p>Reopening this issue. With the advent of Data-on-MDT we will at some point want to allow filesystems with only MDTs to be created. At that point, this check has to be removed. </p> <p>As a starting point, we could add a tunable that allows this behavior to be selected by the admin - return an error if no OSTs are available, or cause the client to block and wait for an OST to become available. I think in the case where an OST was previously available, but they are temporarily offline due to failover, the client should block. If the file being created has a DoM component at the start, then it should not block. </p> <p>Main ticket for remaining work is <a href="https://jira.whamcloud.com/browse/LU-10995" title="DoM2: allow MDT-only filesystems " class="issue-link" data-issue-key="LU-10995">LU-10995</a></p> Related LU-10995 Development End date Mon, 4 Jan 2016 16:09:56 +0000 Rank 1|hzxwrr: Rank (Obsolete) 9223372036854775807 Severity Start date Thu, 24 Dec 2015 16:09:56 +0000