mysql dba系统学习（4）mysql的多实例multi启动停止

mysql的多实例配置安装

 一，什么情况下我们会考虑一台物理服务器上部署多个实例，大致有以下几种情况：

1，采用了数据伪分布式架构的原因，而项目启动初期又不一定有那多的用户量，为此先一组物理数据库服务器，但部署多个实例，方便后续迁移；

2，为规避mysql对SMP架构不支持的缺陷，使用多实例绑定处理器的办法（NUMA处理器必须支持，不过现在大部分处理器都支持的！），把不同的数据库分配到不同的实例上提供数据服务；

3，一台物理数据库服务器支撑多个数据库的数据服务，为提高mysql复制的从机的恢复效率，采用多实例部署；

已经为双主复制的mysql数据库服务器架构，想部分重要业务的数据多一份异地机房的热备份，而mysql复制暂不支持多主的复制模式，且不给用户提供服务，为有效控制成本，会考虑异地机房部署一台性能超好的物理服务器，甚至外加磁盘柜的方式，为此也会部署多实例；

4，传统游戏行业的MMO/MMORPG，以及Web Game，每一个服都对应一个数据库，而可能要做很多数据查询和数据订正的工作，为减少维护而出错的概率，也可能采用多实例部署的方式，按区的概念分配数据库；

 二，mysql的多实例的介绍

         mysqld_multi被设计为了管理实现多个mysqld服务进程   

 三，配置多实例mysqld及初始化

1，创建实例的数据文件目录

[root@test4 ~]# cd /mysql/
[root@test4 mysql]# ls 
data
[root@test4 mysql]# mkdir data2/
[root@test4 mysql]# mkdir data3/

2，初始化多实例mysql
[root@test4 mysql]# mysql_install_db   --datadir=/mysql/data2/  --user=mysqlInstalling 

MySQL system tables...
OK

[root@test4 mysql]# mysql_install_db   --datadir=/mysql/data3/  --user=mysqlInstalling MySQL 

system tables...
OKFilling help tables...
OK
To start mysqld at boot time you have to copy
support-files/mysql.server to the right place for your system
PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
To do so, start the server, then issue the following commands:
/usr/local/mysql/bin/mysqladmin -u root password 'new-password'
/usr/local/mysql/bin/mysqladmin -u root -h test4.wolf.org password 'new-password'
Alternatively you can run:
/usr/local/mysql/bin/mysql_secure_installation
which will also give you the option of removing the test
databases and anonymous user created by default.  This is
strongly recommended for production servers.
See the manual for more instructions.
You can start the MySQL daemon with:
cd /usr/local/mysql ; /usr/local/mysql/bin/mysqld_safe &
You can test the MySQL daemon with mysql-test-run.pl
cd /usr/local/mysql/mysql-test ; perl mysql-test-run.pl
Please report any problems with the /usr/local/mysql/bin/mysqlbug script!

3，配置mysqld的多实例my.cnf文件

(1)配置my.cnf文件详解

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[root@test4 ~]# cat  /etc/my.cnf [mysqld_multi] mysqld =/usr/local/mysql/bin/mysqld_safe mysqladmin =/usr/local/mysql/bin/mysqladmin user =test password =test [client] #password       = your_password port            = 3306 socket          = /tmp/mysql.sock [mysqld3306] port            = 3306 socket          = /tmp/mysql3306.sock skip-external-locking key_buffer_size = 16M max_allowed_packet = 1M table_open_cache = 64 sort_buffer_size = 512K net_buffer_length = 8K read_buffer_size = 256K read_rnd_buffer_size = 512K myisam_sort_buffer_size = 8M log-bin=mysql-bin binlog_format=mixed datadir = /mysql/data server-id       = 1 [mysqld3307] port            = 3307 socket          = /tmp/mysql3307.sock skip-external-locking key_buffer_size = 16M max_allowed_packet = 1M table_open_cache = 64 sort_buffer_size = 512K net_buffer_length = 8K read_buffer_size = 256K read_rnd_buffer_size = 512K myisam_sort_buffer_size = 8M log-bin=mysql-bin binlog_format=mixed datadir = /mysql/data2 server-id       = 1 [mysqld3308] port            = 3308 socket          = /tmp/mysql3308.sock skip-external-locking key_buffer_size = 16M max_allowed_packet = 1M table_open_cache = 64 sort_buffer_size = 512K net_buffer_length = 8K read_buffer_size = 256K read_rnd_buffer_size = 512K myisam_sort_buffer_size = 8M log-bin=mysql-bin binlog_format=mixed datadir = /mysql/data3 server-id       = 1 [mysqldump] quick max_allowed_packet = 16M [mysql] no-auto-rehash [myisamchk] key_buffer_size = 20M sort_buffer_size = 20M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout

（2）启动多实例

[root@test4 ~]# /usr/local/mysql/bin/mysqld_multi  --defaults-file=/etc/my.cnf  start 3308

     [root@test4 ~]# ps aux|grep 3308
root      4887  0.0  0.2 106012  1348 pts/1    S    14:57   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --port=3308 --socket=/tmp/mysql3308.sock --skip-external-locking --key_buffer_size=16M --max_allowed_packet=1M --table_open_cache=64 --sort_buffer_size=512K --net_buffer_length=8K --read_buffer_size=256K --read_rnd_buffer_size=512K --myisam_sort_buffer_size=8M --log-bin=mysql-bin --binlog_format=mixed --datadir=/mysql/data3 --server-id=1
mysql     5034  0.0  1.3 125304  6668 pts/1    Sl   14:57   0:00 /usr/local/mysql/libexec/mysqld --basedir=/usr/local/mysql --datadir=/mysql/data3 --user=mysql --skip-external-locking --key_buffer_size=16M --max_allowed_packet=1M --table_open_cache=64 --sort_buffer_size=512K --net_buffer_length=8K --read_buffer_size=256K --read_rnd_buffer_size=512K --myisam_sort_buffer_size=8M --log-bin=mysql-bin --binlog_format=mixed --server-id=1 --log-error=/mysql/data3/test4.wolf.org.err --pid-file=/mysql/data3/test4.wolf.org.pid --socket=/tmp/mysql3308.sock --port=3308

（3）连接mysql多实例

[root@test4 ~]# mysql  -S  /tmp/mysql3308.sock 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.70-log Source distribution

Copyright (c) 2000, 2013, 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> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| test               |
+--------------------+
3 rows in set (0.01 sec)
  (4)启停多实例musql

            由于是多实例的方式来管理mysql，所以暂时不可以通过如下方式来停止数据库

[root@test4 ~]# /usr/local/mysql/bin/mysqld_multi  --defaults-file=/etc/my.cnf  stop  3308

真正的关闭多实例MySQL的方法是通过配置在/etc/my.cnf中test用户， 

  [root@test4 ~]# mysql -S  /tmp/mysql3308.sock 
mysql> GRANT SHUTDOWN ON *.* TO 'test'@'localhost' IDENTIFIED BY 'TEST' WITH GRANT OPTION;

Query OK, 0 rows affected (0.00 sec)

  [root@test4 ~]# mysqld_multi  --defaults-file=/etc/my.cnf   stop 3306
[root@test4 ~]# mysqld_multi  --defaults-file=/etc/my.cnf   stop 3307
[root@test4 ~]# mysqld_multi  --defaults-file=/etc/my.cnf   stop 3308
[root@test4 ~]# ps aux|grep mysql
root      6148  0.0  0.1 103152   824 pts/1    S+   15:48   0:00 grep mysql

本文出自 “好好活着” 博客，请务必保留此出处http://wolfword.blog.51cto.com/4892126/1241304

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