在Mysql官方帮助文档中，详细记录中Mysql的启动方式，有mysqld_safe、mysql.server、mysql_multi这三种。关于mysql_multi的介绍：

Mysqld_multi可以管理多个帧听不同Unix套接字文件和TCP/IP端口的连接的mysqld进程。它可以启动或停止服务器，或报告它们的当前状态。

即可以管理多个实例。

笔者在之前也介绍过使用mysqld_safe启用多实例的方法，启动和关闭都指定配置文件，实例间是对立的，互不影响。成功的部署了多个实例主从Replication，今天也介绍下mysql_multi多实例管理，配置简单，方便管理。

1、首先配置my.cnf文件，列出我的Mysql配置文件：

[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe#根据自己的mysql目录配置
mysqladmin = /usr/local/mysql/bin/mysqladmin
[mysqld1]
port= 3306
socket= /tmp/mysql3306.sock
basedir=/usr/local/mysql
datadir=/mysqldata/data3306
log-slow-queries=slow_query.txt
long_query_time=2
skip-locking
skip-name-resolve
skip-innodb
max_allowed_packet = 256M
query_cache_size=256M
max_connections=2000
max_connect_errors=10000
key_buffer_size=6000M
read_buffer_size=32M
read_rnd_buffer_size = 32M
myisam_sort_buffer_size=512M
tmp_table_size=1024M
old-passwords
interactive_timeout=60
wait_timeout=60
connect_timeout=60
table_cache=8192
thread_cache_size=512
sort_buffer_size=128M
back_log = 500
thread_concurrency=48
expire_logs_days=10
log-bin=mysql-bin
[mysqld2]
port= 3307
socket= /tmp/mysql3307.sock
basedir=/usr/local/mysql
datadir=/mysqldata/data3307
log-slow-queries=slow_query.txt
long_query_time=2
skip-locking
skip-name-resolve
skip-innodb
max_allowed_packet = 256M
query_cache_size=256M
max_connections=2000
max_connect_errors=10000
key_buffer_size=6000M
read_buffer_size=32M
read_rnd_buffer_size = 32M
myisam_sort_buffer_size=512M
tmp_table_size=1024M
old-passwords
interactive_timeout=60
wait_timeout=60
connect_timeout=60
table_cache=8192
thread_cache_size=512
sort_buffer_size=128M
back_log = 500
thread_concurrency=48
expire_logs_days=10
log-bin=mysql-bin
[mysqldump]
quick
max_allowed_packet = 512M
[mysql]
no-auto-rehash
[isamchk]
key_buffer = 512M
sort_buffer_size = 32M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 512M
sort_buffer_size = 32M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout

2、初始化数据库目录：

shell>cd /usr/local/mysql/;./scripts/mysql_install_db --datadir=/mysqldata/data3307/ --user=mysql
shell>cd /usr/local/mysql/;./scripts/mysql_install_db --datadir=/mysqldata/data3306/ --user=mysql

初始话成功，会提示OK，否则查看数据库目录是否有权限。

3、启动多实例：

shell>/usr/local/mysql/bin/mysqld_multi start 1-2
或
shell>/usr/local/mysql/bin/mysqld_multi start 1
shell>/usr/local/mysql/bin/mysqld_multi start 2

注意这里的1、2对应my.cnf配置文件mysqld1、mysqld2，以此来区分。

4、本机登录Mysql，如3307端口：

shell>mysql -S/tmp/mysql3307.sock
mysql> show variables like 'datadir';
+---------------+----------------------+
| Variable_name | Value|
+---------------+----------------------+
| datadir | /mysqldata/data3307/ |
+---------------+----------------------+
1 row in set (0.00 sec)

4、关闭数据库实例

shell>/usr/local/mysql/bin/mysqld_multi stop 1-2
或
shell>/usr/local/mysql/bin/mysqld_multi stop 1
shell>/usr/local/mysql/bin/mysqld_multi stop 2