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<p class="MsoNormal">The message is part of normal o2iblnd connection setup. It just means the two peers are negotiating the max number of fragments that will be supported.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It is seen because <a href="https://jira.whamcloud.com/browse/LU-15092">https://jira.whamcloud.com/browse/LU-15092</a> changed the default max number of fragments from 256 to 257. If one peer has that patch, but the other doesn’t, then negotiation must occur.<br>
<br>
There is a separate but related issue involving map_on_demand. In some Lustre versions, map_on_demand must be set to 1 in order for the aforementioned negotiation to succeed.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Chris Horn<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">lustre-discuss <lustre-discuss-bounces@lists.lustre.org> on behalf of Einar Næss Jensen <einar.nass.jensen@ntnu.no><br>
<b>Date: </b>Thursday, September 8, 2022 at 6:12 AM<br>
<b>To: </b>Moreno Lazaro Diego (ID) <diego.moreno@id.ethz.ch>, lustre-discuss@lists.lustre.org <lustre-discuss@lists.lustre.org><br>
<b>Subject: </b>Re: [lustre-discuss] max_frags 257 too large<o:p></o:p></span></p>
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<p class="MsoNormal">Thanks for the clarification, Diego<br>
<br>
We are in for an upgrade next month so we might just wait and see :)<br>
<br>
<br>
Best Regards<br>
EInar Næss Jensen<br>
<br>
________________________________________<br>
From: Moreno Lazaro Diego (ID) <diego.moreno@id.ethz.ch><br>
Sent: Thursday, September 8, 2022 13:07<br>
To: Einar Næss Jensen; lustre-discuss@lists.lustre.org<br>
Subject: Re: [lustre-discuss] max_frags 257 too large<br>
<br>
Hi Einar,<br>
<br>
I've seen this in older versions of Lustre-2.12 where map_on_demand=1 on the ko2iblnd module is needed in order to keep compatibility with newer versions. There are a couple of patches where this requirement for map_on_demand was removed though it's now set
by default:<br>
<br>
<a href="https://jira.whamcloud.com/browse/LU-15094">https://jira.whamcloud.com/browse/LU-15094</a>
(don't require map_on_demand to negotiate max_frags)<br>
<a href="https://jira.whamcloud.com/browse/LU-15186">https://jira.whamcloud.com/browse/LU-15186</a>
(set by default map_on_demand)<br>
<br>
I know at least DDN includes these patches on their 2.12.6-ddn8 version. I don't see the patches on the latest 2.12.9 on the community version. Maybe you just need to enable map_on_demand and that could solve it.<br>
<br>
Regards,<br>
<br>
Diego<br>
<br>
On 08.09.22, 11:22, "lustre-discuss on behalf of Einar Næss Jensen" <lustre-discuss-bounces@lists.lustre.org on behalf of einar.nass.jensen@ntnu.no> wrote:<br>
<br>
We have a case of one of our MDS servers stopped working correctly (we have failed over the mdt to other mds server), and while we wait for vendor response, I see something in our logs which I'm curious about:<br>
<br>
LNet: 117894:0:(o2iblnd_cb.c:2631:kiblnd_passive_connect()) Can't accept conn from 10.145.30.168@o2ib (version 12): max_frags 257 too large (256 wanted)<br>
<br>
What does it mean? is it somethinbg to be concerned over?<br>
<br>
<br>
<br>
Best Regards<br>
Einar Næss Jensen<br>
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<br>
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<o:p></o:p></p>
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