以下內容爲在學習MYSQL 過程中的實驗步驟，
mysql多實例（mysqld_multi方式）
1.建立各個實例的目錄
[root@mdw ~]# mkdir /mnt/data/mysql/3306 /mnt/data/mysql/3307 /mnt/data/mysql/3308 -p[root@mdw ~]# chown -R mysql:mysql /mnt/data/mysql/3306 /mnt/data/mysql/3307 /mnt/data/mysql/3308
[root@mdw ~]#
2.初始化各個實例
/usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/mnt/data/mysql/3306 --user=mysql
/usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/mnt/data/mysql/3307 --user=mysql
/usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/mnt/data/mysql/3308 --user=mysql
3.修改配置，my.cnf 配置文件修改後如下：
[root@mdw ~]# cat /etc/my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = root
password = sa123
[mysqld3306]
datadir = /mnt/data/mysql/3306
port = 3306
socket = /tmp/mysql3306.sock
log-bin = /mnt/data/mysql/3306/mysql-bin
pid-file = /mnt/data/mysql/3306/mysql_3306.pid
log-error=/var/log/3306.log
[mysqld3307]
datadir = /mnt/data/mysql/3307
port = 3307
socket = /tmp/mysql3307.sock
log-bin = /mnt/data/mysql/3307/mysql-bin
pid-file = /mnt/data/mysql/3307/mysql_3307.pid
log-error=/var/log/3307.log
[mysqld3308]
datadir = /mnt/data/mysql/3308
port = 3308
socket = /tmp/mysql3308.sock
log-bin = /mnt/data/mysql/3308/mysql-bin
pid-file = /mnt/data/mysql/3308/mysql_3308.pid
log-error=/var/log/3308.log
#[mysqld]
#datadir=/usr/local/mysql/data
#socket=/usr/local/mysql/data/mysql.sock
#user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
#symbolic-links=0
#[mysqld_safe]
#log-error=/var/log/mysqld.log
#pid-file=/var/run/mysqld/mysqld.pid
#[client]
#socket=/usr/local/mysql/data/mysql.sock
[root@mdw ~]#
4.啓動 3306,3307,3308 各端口的mysql 實例
[root@mdw ~]# /usr/local/mysql/bin/mysqld_multi start 3306
[root@mdw ~]# /usr/local/mysql/bin/mysqld_multi start 3307
[root@mdw ~]# /usr/local/mysql/bin/mysqld_multi start 3308
#error 一個錯誤處理
[root@mdw ~]# /usr/local/mysql/bin/mysqld_multi start 3306
WARNING: my_print_defaults command not found.
Please make sure you have this command available and
in your path. The command is available from the latest
MySQL distribution.
ABORT: Can't find command 'my_print_defaults'.
This command is available from the latest MySQL
distribution. Please make sure you have the command
in your PATH.
在.bash_profile 添加路徑：
MYSQL_PATH=/usr/local/mysql/bin;
PATH=$PATH:$HOME/bin:$MYSQL_PATH
export PATH
或者直接命令行輸入：export PATH=/usr/local/mysql/bin:$PATH
/usr/local/mysql/bin/mysqladmin -u root -h mdw password 'new-password'
5.查看端口狀態，看是否正常運行
[root@mdw ~]# netstat -anp | grep 3308
tcp 0 0 :::3308 :::* LISTEN 31535/mysqld
unix 2 [ ACC ] STREAM LISTENING 496621 31535/mysqld /tmp/mysql3308.sock
[root@mdw ~]# netstat -anp | grep 3307
tcp 0 0 :::3307 :::* LISTEN 31372/mysqld
unix 2 [ ACC ] STREAM LISTENING 496593 31372/mysqld /tmp/mysql3307.sock
[root@mdw ~]# netstat -anp | grep 3306
tcp 0 0 :::3306 :::* LISTEN 31211/mysqld
unix 2 [ ACC ] STREAM LISTENING 496460 31211/mysqld /tmp/mysql3306.sock
[root@mdw ~]#
6.初始化密碼
6.1 實例：3306,
/usr/local/mysql/bin/mysqladmin -u root password "sa123" -S /tmp/mysql3306.sock
/usr/local/mysql/bin/mysql -uroot -pCleverCode123 -S /tmp/mysql3306.sock
grant all privileges on *.* to 'root'@'127.0.0.1' identified by 'sa123' with grant option;
flush privileges;
/usr/local/mysql/bin/mysqladmin -u root password "saPsd" -S /tmp/mysql3306.sock
實例：3307
/usr/local/mysql/bin/mysqladmin -u root password "sa123" -S /tmp/mysql3307.sock
/usr/local/mysql/bin/mysql -uroot -psa123 -S /tmp/mysql3307.sock
grant all privileges on *.* to 'root'@'127.0.0.1' identified by 'sa123' with grant option;
flush privileges;
實例：3308
/usr/local/mysql/bin/mysqladmin -u root password "sa123" -S /tmp/mysql3308.sock
/usr/local/mysql/bin/mysql -uroot -pCleverCode123 -S /tmp/mysql3308.sock
grant all privileges on *.* to 'root'@'127.0.0.1' identified by 'sa123' with grant option;
flush privileges;
操作明細：
[root@mdw ~]# /usr/local/mysql/bin/mysqladmin -u root password "sa123" -S /tmp/mysql3306.sock
Warning: Using a password on the command line interface can be insecure.
[root@mdw ~]# /usr/local/mysql/bin/mysql -uroot -psa123 -S /tmp/mysql3306.sock
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.6.35-log Source distribution
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> grant all privileges on *.* to 'root'@'127.0.0.1' identified by 'sa123' with grant option;
Query OK, 0 rows affected (0.02 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql>
參考：
http://blog.csdn.net/clevercode/article/details/47659457
