日期:2014-05-16  浏览次数:20715 次

[Linux] 利用logrotate对MySQL日志进行轮转

日志轮转特别适用于具有固定文件名的日志文件,比如MySQL的出错日志、常规查询日志、慢查询日志等。Linux系统有一个非常好用的根据logratate可以实现自动轮转,本文介绍它的原理和用法。

默认情况下,logratate部署为每天运行的cron job,你可以在目录/etc/cron.daily里找到名为logratate的配置文件。那么它是在每天的上面时候运行的呢?打开文件/etc/crontab就知道了,下面是我机器上的情况:

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly
从上面的配置我们可以知道,/etc/cron.daily是在每天凌晨4:02执行。也就是说,每天4:02分/etc/cron.daily/logratate将会自动执行,下面是它的内容:

#!/bin/sh

/usr/sbin/logrotate /etc/logrotate.conf
EXITVALUE=$?
if [ $EXITVALUE != 0 ]; then
    /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"
fi
exit 0
从上面我们可以知道,logratate默认的配置文件是/etc/logratate.conf,下面是它的内容:

EXITVALUE=$?
if [ $EXITVALUE != 0 ]; then
    /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"
fi
exit 0
[root@lx202 /etc/cron.daily ]# cat /etc/logrotate.conf
# see "man logrotate" for details
# rotate log files weekly
weekly

# keep 4 weeks worth of backlogs
rotate 4

# create new (empty) log files after rotating old ones
create

# uncomment this if you want your log files compressed
#compress

# RPM packages drop log rotation information into this directory
include /etc/logrotate.d

# no packages own wtmp -- we'll rotate them here
/var/log/wtmp {
    monthly
    minsize 1M
    create 0664 root utmp
    rotate 1
}

/var/log/btmp {
    missingok
    monthly
    minsize 1M
    create 0600 root utmp
    rotate 1
}
从上面我们可以知道,这个默认的配置文件将读取目录/etc/logrotate.d,所以我们只要把自己写的配置文件放到该目录下即可。

MySQL本省提供了一个rotate的参考配置文件,在support-files目录下,文件名为mysql-log-rotate,内容如下:

# This logname can be set in /etc/my.cnf
# by setting the variable "err-log"
# in the [safe_mysqld] section as follows:
#
# [safe_mysqld]
# err-log=/opt/mysql/data/mysqld.log
#
# If the root user has a password you have to create a
# /root/.my.cnf configuration file with the following
# content:
#
# [mysqladmin]
# password = <secret>
# user= root
#
# where "<secret>" is the password.
#
# ATTENTION: This /root/.my.cnf should be readable ONLY
# for root !

/opt/mysql/data/mysqld.log {
        # create 600 mysql mysql
        notifempty
        daily
        rotate 3
        missingok
        compress
    postrotate
        # just if mysqld is really running
        if test -x /opt/mysql/bin/mysqladmin && \
           /opt/mysql/bin/mysqladmin ping &>/dev/null
        then
           /opt/mysql/bin/mysqladmin flush-logs
        fi
    endscript
}

logrotate常见选项:

选项 含义
compress 压缩日志文件的所有非当前版本
copy 复制当前的日志文件,忽略create参数