利用logrotate对MySQL日志进行轮转

来源：本站整理作者：梦在深巷时间：2014-01-13 16:37:20

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，logrotate部署为每天运行的cron job，你可以在目录/etc/cron.daily里找到名为logrotate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：

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1 2 3 4 5 6 7 8 9 10	`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/logrotate将会自动执行，下面是它的内容：

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1 2 3 4 5 6 7 8	`#!/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：

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37	`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：

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36	`# 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:

利用logrotate对MySQL日志进行轮转

我们只要根据自己的需要，修改相应配置即可，下面是一个例子：

1)创建MySQL root密码文件

vi /root/.my.cnf

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1 2 3	`[mysqladmin]` `password = ***` `user= root`

chmod 600 /root/.my.cnf

2)把mysql-log-rotate拷贝至/etc/logrotate.d目录下，修改其内容为：

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17	`/data/mysql/log/slow.log` `/data/mysql/log/alert.log {` `create 600 mysql mysql` `notifempty` `daily` `rotate 7` `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` `}`

3)执行以下命令测试

/usr/sbin/logrotate -f /etc/logrotate.d/mysql-log-rotate