为mysql添加端口号为3309的实例：
一 添加新端口的数据目录:mkdir /usr/local/mysql/var1
二 修改my.cnf的配置信息：
1将client的默认端口3306注释掉
[client]
#password = your_password
#port = 3306
socket = /tmp/mysql.sock
2 添加mysqld_multi配置信息
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = root
#password = root
3 添加新实例对应的端口及参数信息：
[mysqld2]
user = mysql
port = 3309
socket = /tmp/mysql1.sock
pid-file=/usr/local/mysql/var1/db-app1.pid
log=/usr/local/mysql/var1/db-app1.log
datadir = /usr/local/mysql/var1/
basedir = /usr/local/mysql
user = root
三 初始化数据目录 为新端口安装数据库：(也可以将mysql原来的数据文件目录cp过来 cp /usr/local/mysql/var /usr/local/mysql/var2 chown ...chgrp...)
sudo /usr/local/mysql/bin/mysql_install_db --datadir=/usr/local/mysql/var1 --user=mysql
四 修改var1的用户及用户组: (注意 修改权限必须要再安装mysql数据库之后)
sudo chown -R mysql var1
sudo chgrp -R mysql var1
五
配置多实例启动脚本
cp /home/sunny.zhao/ mysql-5.1.51/support-files/mysqld_multi.server /etc/init.d/mysqld_multi.server
检查mysqld_multi.server 的 basedir和bindir安装路径basedir=/usr/local/mysqlbindir=/usr/local/mysql/bin
六 关闭mysql服务 mysqladmin -uroot -p*** shutdown
#查看数据库状态#结果都为没有运行Reporting MySQL serversMySQL server from group: mysqld1 is not runningMySQL server from group: mysqld2 is not running
sudo mysqld_multi --defaults-extra-file=/etc/my.cnf start
#启动具体某一个实例可在start、stop后面加上具体数据1,2,3等
sudo mysqld_multi --defaults-extra-file=/etc/my.cnf report
登录端口为3309mysql实例： mysql -uroot -p -h127.0.0.1 -P3309
#通过sock文件登录mysql -uroot -p -S /usr/local/var/mysql1/mysql1.sock #查看socket文件mysql> SHOW VARIABLES LIKE 'socket';
+---------------+------------------+
| Variable_name | Value |
+---------------+------------------+
| socket | /tmp/mysql1.sock |
+---------------+------------------+
1 row in set (0.00 sec)
mysql> SHOW VARIABLES LIKE '%pid%';
+---------------+-----------------------------------+
| Variable_name | Value |
+---------------+-----------------------------------+
| pid_file | /usr/local/mysql/var1/db-app1.pid |
+---------------+-----------------------------------+
1 row in set (0.00 sec)
mysqld_multi stop 1,2 关闭1，2数据库。
sudo mysqld_multi --defaults-extra-file=/etc/my.cnf stop 1-2
或者 $ sudo mysqladmin -uroot -pmysql -P3312 -h127.0.0.1 shutdown
修改密码： bin]$ mysqladmin -uroot -P3309 -h127.0.0.1 password ***
登录：bin]$ mysql -uroot -pmysql -h127.0.0.1 -P3309
检查MySQL启动状态
netstat -ntlp | grep 33 查看MySQL端口启动状态
[ bin]$ netstat -ntl | grep 33
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:3309 0.0.0.0:* LISTEN
ls -l /tmp/*sock* 查看MySQL访问连接
y bin]$ ls -l /tmp/*sock*
srwxrwxrwx 1 root root 0 Sep 19 09:08 /tmp/mysql1.sock
srwxrwxrwx 1 mysql mysql 0 Jul 20 14:50 /tmp/mysql2.sock
srwxrwxrwx 1 mysql mysql 0 Sep 19 10:16 /tmp/mysql.sock
srwxrwxrwx 1 root root 0 Sep 19 10:13 /tmp/mysql.sock2
ps -ef | grep mysql 查看MySQL实例进程
root 7281 1 0 10:13 pts/5 00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --socket=/tmp/mysql.sock2 --port=3309 --pid-file=/usr/local/mysql/var1/hostname.pid2 --datadir=/usr/local/mysql/var1 --user=root --socket=/tmp/mysql.sock2 --port=3309 --pid-file=/usr/local/mysql/var1/hostname.pid2 --datadir=/usr/local/mysql/var1 --user=root
root 7453 7281 0 10:13 pts/5 00:00:00 /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/var1 --user=root --log-error=/usr/local/mysql/var1/mysql-test-woody.err --pid-file=/usr/local/mysql/var1/hostname.pid2 --socket=/tmp/mysql.sock2 --port=3309
root 7838 1 0 10:16 pts/5 00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --port=3306 --socket=/tmp/mysql.sock --skip-external-locking --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/var/ .... --pid-file=/usr/local/mysql/var/mysql.pid
--log-error=/usr/local/mysql/var/mysql.err --pid-file=/usr/local/mysql/var/mysql.pid --socket=/tmp/mysql.sock --port=3306
不知道为什么用top命令查看进程的时候为什么只能看到一个 看不到两个进程 ？？？？？？？
[*@*top]
8216 mysql 20 0 168m 28m 3872 S 0.0 2.9 0:00.34 /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql/ --datadir=/usr/local/mysql/var/ --user=mysql --skip-external-locking --key_b相关不错的博文：http://alicsd.iteye.com/blog/856939