In a cloud server, Nginx's access log is written to a unified log file by default, such as /var/log/nginx/access.log. However, if the website traffic is large, the log file will grow rapidly, which is not conducive to management and analysis. Therefore, regular segmentation (by day, hour, etc.) of log storage is a common optimization method. The following are several ways to implement Nginx access log segmentation:

　　Method 1: It is recommended to use logrotate to automatically segment logs

　　Logrotate is a built-in log management tool in Linux that can automatically archive, compress and delete old logs regularly.

　　Configure logrotate

　　Add or modify the following content in /etc/logrotate.d/nginx:

/var/log/nginx/access.log {
    daily                 # Split by day (optional hourly, weekly, monthly)
    rotate 7              # Keep 7 days of logs
    missingok             # Ignore non-existent log files
    notifempty             # Empty files are not processed
    compress              # Use gzip to compress logs
    delaycompress         # Delay compression for one day to prevent the log from being compressed while it is still being written
    postrotate
        systemctl reload nginx > /dev/null 2>&1  # Reload Nginx to use the new log file
    endscript
}

　　Manually testing logrotate

　sudo logrotate -f /etc/logrotate.d/nginx

　　Method 2: Manual shell script timed splitting

　　Applicable to scenarios that require customized log format or customized management.

　　Create a log splitting script

　　Create a new script /usr/local/bin/nginx_log_split.sh:

#!/bin/bash

# Define the log storage directory
LOG_DIR="/var/log/nginx"
DATE=$(date +%Y-%m-%d)

# Back up the current log
mv $LOG_DIR/access.log $LOG_DIR/access-$DATE.log

# Reopen the log file
kill -USR1 $(cat /run/nginx.pid)

　　kill -USR1 $(cat /run/nginx.pid) allows Nginx to reopen the log file without interrupting the service.

　　Give execution permission

 chmod +x /usr/local/bin/nginx_log_split.sh

　　Configure crontab for scheduled execution

　　Edit crontab:

 crontab -e

　　Add to:

 0 0 * * * /usr/local/bin/nginx_log_split.sh

　　Indicates that log segmentation is run at midnight every day.

　　Method 3: Nginx automatically segments logs by day (based on variables)

　　If you want to segment logs by date directly in Nginx, you can use the $time_local variable.

　　Modify Nginx configuration

　　Open /etc/nginx/nginx.conf or site configuration file:

 access_log /var/log/nginx/access-$time_iso8601.log;

　　However, Nginx does not support dynamic log file paths by default, so this method only works with OpenResty or specially compiled Nginx versions.