systemd journald journalctl

journalctl

https://wiki.ubuntuusers.de/systemd/journalctl/

• Give times
  • journalctl --since="yesterday"
  • journalctl --since="today"
  • journalctl --since="-1h" // last hour
• Find unclean shutdowns during last week (power cut)
  • journalctl --no-pager --since="-1 month" | grep --context 1 ' Reboot ' | grep -zP '(?<!Journal stopped)\n\-\- Reboot'

journald

https://wiki.ubuntuusers.de/systemd/journald/

https://www.freedesktop.org/software/systemd/man/journald.conf.html

https://www.loggly.com/ultimate-guide/managing-journal-size/

• Log files are in
  • /var/log/journal
• Edit config
  • vi /etc/systemd/journald.conf

    • # persistent = store to disk in /var/log/journal
      #Storage=auto
      Storage =persistent
      
      # Limit the log size to given value, otherwise 4G
      #SystemMaxUse=
      SystemMaxUse=2G

• Restart
  • systemctl restart systemd-journald
• Show persitent log size
  • journalctl --disk-usage
• Reduce storage size to 1G
  • journalctl --vacuum-size=1G
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Show all running services

• service --status-all