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<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Do you mean you've never hit client eviction or dirty page discard before?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">What was your previous Lustre version?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Dirty page discard warning exists for a long time, since Lustre 2.4.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Eviction happens for lots of reason. Evictions just mean this client did not respond in 100 sec to this OSS. It could be due to network being overloaded, hardware issue on one of these
hosts, client not responding due to CPU being overloaded, or indeed a bug. You should first try to understand why these eviction happened.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Verify the server and client load at that time (CPU, network, etc…). Verify the impacted files and the application accessing them. What's the application I/O pattern? Is it putting a
strong pressure on these files? File name could be obtained using the FID and 'lfs fid2path MOUNT_POINT FID'.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Aurélien<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><b><span style="font-size:12.0pt;color:black">De :
</span></b><span style="font-size:12.0pt;color:black">lustre-discuss <lustre-discuss-bounces@lists.lustre.org> au nom de
</span><span style="font-size:12.0pt;font-family:"MS Gothic";color:black">肖正</span><span style="font-size:12.0pt;font-family:"PingFang TC",sans-serif;color:black">刚</span><span style="font-size:12.0pt;color:black"> <guru.novice@gmail.com><br>
<b>Date : </b>dimanche 30 août 2020 à 07:41<br>
<b>À : </b>Andreas Dilger <adilger@whamcloud.com><br>
<b>Cc : </b>lustre-discuss <lustre-discuss@lists.lustre.org><br>
<b>Objet : </b>RE: [EXTERNAL] [lustre-discuss] some clients dmesg filled up with "dirty page discard"<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Hi, Andreas<span style="font-family:"MS Gothic"">，</span><o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Thanks for your reply.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Maybe this is a bug?<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">We never hit this before update client to 2.12.5<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Andreas Dilger <<a href="mailto:adilger@whamcloud.com">adilger@whamcloud.com</a>>
<span style="font-family:"MS Gothic"">于</span>2020<span style="font-family:"MS Gothic"">年</span>8<span style="font-family:"MS Gothic"">月</span>29<span style="font-family:"MS Gothic"">日周六</span>
<span style="font-family:"MS Gothic"">下午</span>6:37<span style="font-family:"MS Gothic"">写道：</span><o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">On Aug 25, 2020, at 17:42, <span style="font-family:"MS Gothic"">
肖正</span><span style="font-family:"PingFang TC",sans-serif">刚</span> <<a href="mailto:guru.novice@gmail.com" target="_blank">guru.novice@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">no, on oss we found only the client who reported "
<span style="font-family:Helvetica;color:#202124">dirty page discard</span> " being evicted.
<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">we hit this again last night, and on oss we can see logs like:<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">"<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">[Tue Aug 25 23:40:12 2020] LustreError: 14278:0:(ldlm_lockd.c:256:expired_lock_main()) ### lock callback timer expired after 100s: evicting client at 10.10.3.223@o2ib ns: filter-public1-OST0000_UUID lock: ffff9f1f91cba880/0x3fcc67dad1c65842
lrc: 3/0,0 mode: PR/PR res: [0xde2db83:0x0:0x0].0x0 rrc: 3 type: EXT [0->18446744073709551615] (req 0->270335) flags: 0x60000400020020 nid: 10.10.3.223@o2ib remote: 0xd713b7b417045252 expref: 7081 pid: 25923 timeout: 21386699 lvb_type: 0<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">It isn't clear what the question is here. The "dirty page discard" message means that unwritten data from the client was discarded because the client was evicted and the lock covering this data was revoked by
the server because the client was not responsive.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">Anymore , we exec lfsck on all servers, result is<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt">There is no need for LFSCK in this case. The file data was not written, but a client eviction does not result in the filesystem becoming inconsistent.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><span style="color:black">Cheers, Andreas<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><span style="color:black">--<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><span style="color:black">Andreas Dilger<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><span style="color:black">Principal Lustre Architect<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:35.4pt"><span style="color:black">Whamcloud<o:p></o:p></span></p>
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