What does linux journal mean?

Linux journal is a component of systemd and is processed by journald; used to capture system log information, kernel log information, and information from the original RAM disk, early startup information, and write STDOUT and STDERR data in all services Streaming information.

#The operating environment of this tutorial: linux5.9.8 system, Dell G3 computer.

What does linux journal mean?

journal is a component of systemd in centos7 and is processed by journald. Captures system log information, kernel log information, and information from the raw RAM disk, early boot information, and information written to the STDOUT and STDERR data streams in all services.

It can be said that it is a new system log method created for Linux servers. These log information are written to binary files, read using journalctl, and stored under /run/log/ by default.

What is the difference or relationship between this and the previous rsyslog?

systemd-journald.service: the main message receiver, provided by systemd;

rsyslog.service: mainly logs in to system and network services;

In addition to retaining the existing rsyslog.service, CentOS 7 actually uses systemd's own login file log management function at the upstream end! He uses the systemd-journald.service service to support it. Basically, the system is managed by systemd. For all services started by systemd, if some problems or normal messages occur during the restart or termination process, the message will be recorded in binary form by systemd-journald.service. down, and then send this message to rsyslog.service for further recording.

Systemd-journald.service records are mainly placed in memory, so the access performance is relatively good. We can also view the login files of different services through journalctl and systemctl status unit.service! The advantage of this is that the log files can be viewed by you along with individual services. The processing of a single service is much easier than going to /var/log/messages to find a needle in a haystack!

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