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</o:shapelayout></xml><![endif]--></head><body lang=ZH-CN link="#0563C1" vlink="#954F72" style='word-wrap:break-word;text-justify-trim:punctuation'><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hi, I have already read man page of journalctl and made some experiments with the command.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>All the efforts made me more confused. So, I would like to beg some help here.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>My system is Ubuntu 20.04.3 LTS.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My procedures:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Create a .conf file for systemd-jounald.service with following content:<br>[Journal]<br>Storage=volatile<br><br><o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Restart systemd-jounald.service<br><br>sudo systemctl restart systemd-jounald.service<br><br><o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Check the status of journald and ensure it is writing log into memory.<br><br>systemctl status systemd-jounald.service<br><br>The result is like:<br><br>Runtime Journal (/run/log/journal/...)<br>which informed me that .conf file worked well.<br><br><o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Comment out the Storage option<br>[Journal]<br>#Storage=volatile<br><br><br><o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>5.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>Restart journald<br><br>sudo systemctl restart system-journald<br><br><o:p></o:p></span></p><p class=MsoListParagraph style='margin-left:18.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US><span style='mso-list:Ignore'>6.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US>check status again and you will see that flush already been done<br><br>systemctl status system-journald<br><br>with feedback including<br><br><span style='background:silver;mso-highlight:silver'>Time spent on flushing to /var/log/journal/machineID/ is 282.991ms for 1483 entries.</span><br><br>which means flush had been done.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Now that the operation of flush can be done automatically when you switch from Storage=volatile to #Storage=volatile, why do we still need journalctl --flush?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I believe there are some reasons for the existence of this switch for journalctl.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Hopefully, I can find some help here.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Thank you!<o:p></o:p></span></p></div></body></html>