Log Rotate in Linux

             When we work with Linux, we will at least encounter the phenomenon of /var/log being full. So what do we do in this case:

Step 1: We need to define what folder or item has a big amount of use.

• du -h /var/log/ | sort -rh | head -n 5

Step 2: We can see we have a list of item with a big size.

Step 3: The item “message” has a large capacity so we will consider it. This is an incremental item, It will gradually increase in capacity every day. So we need setup a log rotation for this.

So what is log rotation?

Log rotation is the process of managing and maintaining log files on a Linux system to prevent them from becoming too large and consuming excessive disk space. Log rotation involves renaming, compressing, and deleting log files according to a set schedule or when certain conditions are met.

There are several tools available for log rotation in Linux, with the most commonly used tool being logrotate. It is a system utility that is typically included with most Linux distributions and is used to automate the rotation of log files.

To configure log rotation using logrotate, you need to create a configuration file for each log file or set of log files that you want to rotate. These configuration files are typically stored in the /etc/logrotate.d directory.

Step 4 : Create a new configuration file for the log file you want to rotate (e.g., message):

 

·        rotate 5: Keeps up to 5 rotated log files.

·        size 100M: Rotates the log file when it reaches 100 megabytes.

·        compress: Compresses rotated log files using gzip.

·        missingok: Ignores errors if the log file is missing.

·        notifempty: Does not rotate the log file if it is empty.

·        copytruncate: Truncates the original log file instead of renaming.

Save and exit the configuration file.

Step 5: Test the logrotate configuration to ensure there are no syntax errors:

·         logrotate -d /etc/logrotate.d/mesage

Step 6 : One the configuration is validated, run logrotate to rotate the log file:

·         logrotate -f /etc/logrotate.d/message

cording to the configured settings.

Now, logrotate will automatically rotate the log file based on the defined size limit, keeping multiple rotated log files as specified.