Linux常见日志级别(从低到高):
/etc/syslog.conf/etc/rsyslog.conf 或 /etc/rsyslog.d/*.conf。*.* /var/log/syslog;level(如*.warning /var/log/syslog)。service.* /var/log/service.log;level(如authpriv.* /var/log/secure)。sudo systemctl restart rsyslog。/etc/systemd/journald.conf。SystemMaxUse=100M:限制日志大小。journalctl命令过滤日志级别(如journalctl -p err查看错误日志)。sudo systemctl restart systemd-journald。/etc/nginx/nginx.conf中error_log级别(如error_log /var/log/nginx/error.log warn;)。/etc/my.cnf中log_warnings(0-3,0为无警告)。/etc/httpd/conf/httpd.conf中LogLevel(如LogLevel error)。sudo systemctl restart nginx/mysql/apache2。journalctl -f:实时监控日志。tail -f /var/log/syslog:查看系统日志。logrotate工具自动轮转(编辑/etc/logrotate.conf)。sudo journalctl --vacuum-size=100M。sudo chown root:adm /var/log/syslog,chmod 640)。WARNING或ERROR,减少日志量。DEBUG或INFO,便于调试。参考来源:[1,2,3,4,5,6,7,8,9,10,11,12]