Mysql安装环境简介：
最近在做MHA。已经安装完毕heartbeat和drbd，现在准备安装Mysql。
Mysql安装目录：/opt/mysql
Mysql数据目录：/data/mysql
备注：/data目录实际是drbd需要同步到备节点的磁盘分区
[[email protected] src]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 9.5G 2.0G 7.1G 22% /
tmpfs 932M 0 932M 0% /dev/shm
/dev/sda1 190M 58M 123M 32% /boot
/dev/drbd0 19G 832M 17G 5% /data
一、Mysql免编译安装（大家可以直接复制在命令行执行或保存至shell脚本）
#1、解压配置
yum install -y libaio-devel
cd /usr/local/src
[ ! -f mysql-5.5.49-linux2.6-x86_64.tar.gz ] && \
wget http://mirrors.sohu.com/mysql/MySQL-5.5/mysql-5.5.49-linux2.6-x86_64.tar.gz
tar zxf mysql-5.5.49-linux2.6-x86_64.tar.gz
mkdir /opt/
mv mysql-5.5.49-linux2.6-x86_64 /opt/mysql-5.5.49
ln -s /opt/mysql-5.5.49 /opt/mysql
#2、创建用户
if ! id mysql;then
useradd mysql -s /sbin/nologin -M
fi
#可以减写：! id mysql && useradd mysql -s /sbin/nologin -M ####
#还有一种脱裤子放屁的做法。
#groupadd mysql
#useradd -g mysql-M mysql
#用useradd mysql时就会创建mysql组，搞不懂为什么还先添加组
#3、初始化数据库，单实例启动
/opt/mysql/scripts/mysql_install_db --datadir=/data/mysql --basedir=/opt/mysql --user=mysql
cp /etc/my.cnf /etc/my.cnf.ori
grep -Ev "#|^$" /opt/mysql/support-files/my-innodb-heavy-4G.cnf > /etc/my.cnf
cp /opt/mysql/support-files/mysql.server /etc/init.d/mysqld
chkconfig mysqld on
#chmod +x /etc/init.d/mysqld (默认已有x权限）
#4、添加环境变量
echo "PATH=/opt/mysql/bin:$PATH" >> /etc/profile
. /etc/profile
#4、修改/etc/my.cnf或/etc/init.d/mysqld (暂时不修改，让脚本启动报错）
basedir=/opt/mysql
datadir=/data/mysql
***************************************************************************************
1、安装错误
[[email protected] src]#/opt/mysql/scripts/mysql_install_db --datadir=/data/mysql --basedir=/opt/mysql--user=mysql
Installing MySQL system tables...
/opt/mysql/bin/mysqld: errorwhile loading shared libraries: libaio.so.1: cannot open shared object file: Nosuch file or directory
解决：yum install -y libaio-devel
2、启动报错1：没指定basedir和datadir
[[email protected] src]#service mysqld start
/etc/init.d/mysqld: line 256: my_print_defaults: command notfound
/etc/init.d/mysqld: line 276: cd: /usr/local/mysql: No suchfile or directory
Starting MySQL ERROR!Couldn‘t find MySQL server (/usr/local/mysql/bin/mysqld_safe)
3、启动报错2
如果指定了basedir=/opt/mysql,但datadir= 为空时，启动会报错。
[[email protected] src]#service mysqld restart
ERROR! MySQL server PID file could not befound!
Starting MySQL.ERROR! The server quit without updating PID file (/opt/mysql/data/mysql1.pid).
[[email protected] src]#vi /etc/init.d/mysqld
4、启动报错3
也是basedir和datadir都没指定
[[email protected] src]#service mysqld restart
/etc/init.d/mysqld:line 256: my_print_defaults: command not found
/etc/init.d/mysqld:line 256: my_print_defaults: command not found
ERROR! MySQL server PID file could not befound!
/etc/init.d/mysqld:line 256: my_print_defaults: command not found
/etc/init.d/mysqld:line 276: cd: /usr/local/mysql: No such file or directory
Starting MySQLERROR! Couldn‘t find MySQL server (/usr/local/mysql/bin/mysqld_safe)
***********************************************************************************
前几天解决了生产环境的脚本报错的问题，现把报错原理分析总结下：
请看下面/etc/init.d/mysqld的启动脚本加粗部分解释。
# If you install MySQL on some other placesthan /usr/local/mysql, then you
# have to do one of the following things for thisscript to work:
#
# - Run thisscript from within the MySQL installation directory
# - Create a/etc/my.cnf file with the following information:
# [mysqld]
# basedir=<path-to-mysql-installation-directory>
# - Add the aboveto any other configuration file (for example ~/.my.ini)
# and copy my_print_defaults to /usr/bin
# - Add the pathto the mysql-installation-directory to the basedir variable
# below.
#
# If you want toaffect other MySQL variables, you should make your changes
# in the/etc/my.cnf, ~/.my.cnf or other MySQL configuration files.
# If you changebase dir, you must also change datadir. These may get
# If you changebase dir, you must also change datadir. These may get
# overwritten bysettings in the MySQL configuration files.
basedir=
datadir=
# Default value,in seconds, afterwhich the script should timeout waiting
# for serverstart.
# Value here isoverriden by value in my.cnf.
# 0 means don‘twait at all
# Negative numbersmean to wait indefinitely
service_startup_timeout=900
# Lock directoryfor RedHat / SuSE.
lockdir=‘/var/lock/subsys‘
lock_file_path="$lockdir/mysql"
# The followingvariables are only set for letting mysql.server find things.
# Set somedefaults
mysqld_pid_file_path=
if test -z "$basedir"
then
basedir=/usr/local/mysql
bindir=/usr/local/mysql/bin
if test -z"$datadir"
then
datadir=/usr/local/mysql/data
fi
sbindir=/usr/local/mysql/bin
libexecdir=/usr/local/mysql/bin
else
bindir="$basedir/bin"
if test -z"$datadir"
else
bindir="$basedir/bin"
if test -z"$datadir"
then
datadir="$basedir/data"
fi
sbindir="$basedir/sbin"
libexecdir="$basedir/libexec"
fi
翻译：
1、如果basedir没有指定mysql安装路径，启动脚本就会以/usr/local/mysql做为安装路径启动。所以mysql没有安装在/usr/local下，启动必失败
2、如果basedir=/opt/mysql指定了mysql安装路径，并且mysql安装的路径是在/opt/mysql情况下。但datadir= 为空时，启动脚本会将$basedir/data（即/opt/mysql/data)做为mysql的数据目录。平时我们习惯将data目录放在/data/mysql下。此时启动会报错：
Starting MySQL. ERROR! The server quit without updatingPID file (/opt/mysql/data/mysql1.pid).
3、总结：用/etc/init.d/mysql启动时，最好在/etc/init.d/mysqld里设置basedir和datadir的值。或者在/etc/my.cnf 里[mysqld]下添加
[mysqld]
#port = 3306
socket = /tmp/mysql.sock
basedir=/opt/mysql
datadir=/data/mysql
不知道有没说明白。 建议大家再看看mysql启动脚本的文件。
心得：最近mysql遇到不少问题，庆幸大部分出错都能通过日志在百度上搜索出来。说明mysql使用的火热程度及大家的分享精神