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