配置MySQL数据库单机多实例

一、什么是MySQL多实例
简单的说就是在一台机器上开启多个不同的服务端口（例如：3306、3307），运行多个mysql服务进程，这些服务进程通过不同的socket监听不同的服务端口来提供各自的服务。
这些mysql多实例共用一套mysql安装程序，使用不同（也可以相同）的my.cnf配置文件、启动程序、数据文件。在提供服务时，多实例mysql在逻辑上看来是各自独立的，多个实例是根据配置文件中配置的参数来获取服务器相关硬件资源。
二、MySQL常见应用场景
由于公司业务访问量不是很大，服务器的资源基本都是浪费的，这时候很适合使用多实例的应用，如果对SQL语句优化做的比较好，mysql多实例是一个很值得使用的技术，即使并发很大，合理分配系统资源，也不会有太大问题。
三、MySQL多实例常见配置方案
3.1 安装MySQL数据库
具体安装方法，请参见 编译方式安装MySQL数据库 。
3.2 配置多实例
3.2.1 创建多实例目录

[root@mysql-multi ~]# mkdir -p /data/{3306,3307}/data
[root@mysql-multi ~]# tree /data
/data
├── 3306
│   └── data
└── 3307
└── data

3.2.2 将数据目录及临时目录授权mysql用户（在安装mysql之前已经创建mysql用户组和用户）

[root@mysql-multi ~]# chown -R mysql.mysql /data
[root@mysql-multi ~]# chmod -R 1777 /tmp
[root@mysql-multi ~]# ls -ld /data/{3306,3307}/data
drwxr-xr-x. 2 mysql mysql 4096 1月  18 22:40 /data/3306/data
drwxr-xr-x. 2 mysql mysql 4096 1月  18 22:40 /data/3307/data

3.2.3 创建配置文件my.cnf

3306端口

3307端口

[client] port = 3306 socket = /data/3306/mysql.sock [mysql] no-auto-rehash [mysqld] user = mysql port = 3306 socket = /data/3306/mysql.sock basedir = /application/mysql datadir = /data/3306/data open_files_limit = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_cache = 614 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k #default_table_type = InnoDB thread_stack = 192K #transaction_isolation = READ-COMMITTED tmp_table_size = 2M max_heap_table_size = 2M long_query_time = 1 #log_long_format #log-error = /data/3306/error.log #log-slow-queries = /data/3306/slow.log pid-file = /data/3306/mysql.pid log-bin = /data/3306/mysql-bin relay-log = /data/3306/relay-bin relay-log-info-file = /data/3306/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M #myisam_sort_buffer_size = 1M #myisam_max_sort_file_size = 10G #myisam_max_extra_sort_file_size = 10G #myisam_repair_threads = 1 #myisam_recover lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 1 innodb_additional_mem_pool_size = 4M innodb_buffer_pool_size = 32M innodb_data_file_path = ibdata1:128M:autoextend innodb_file_io_threads = 4 innodb_thread_concurrency = 8 innodb_flush_log_at_trx_commit = 2 innodb_log_buffer_size = 2M innodb_log_file_size = 4M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 innodb_file_per_table = 0 [mysqldump] quick max_allowed_packet = 2M [mysqld_safe] log-error=/data/3306/err_mysql_3306.err pid-file=/data/3306/mysqld.pid

[client] port = 3307 socket = /data/3307/mysql.sock [mysql] no-auto-rehash [mysqld] user = mysql port = 3307 socket = /data/3307/mysql.sock basedir = /application/mysql datadir = /data/3307/data open_files_limit = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_cache = 614 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k #default_table_type = InnoDB thread_stack = 192K #transaction_isolation = READ-COMMITTED tmp_table_size = 2M max_heap_table_size = 2M #long_query_time = 1 #log_long_format #log-error = /data/3307/error.log #log-slow-queries = /data/3307/slow.log pid-file = /data/3307/mysql.pid #log-bin = /data/3307/mysql-bin relay-log = /data/3307/relay-bin relay-log-info-file = /data/3307/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M #myisam_sort_buffer_size = 1M #myisam_max_sort_file_size = 10G #myisam_max_extra_sort_file_size = 10G #myisam_repair_threads = 1 #myisam_recover lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 3 innodb_additional_mem_pool_size = 4M innodb_buffer_pool_size = 32M innodb_data_file_path = ibdata1:128M:autoextend innodb_file_io_threads = 4 innodb_thread_concurrency = 8 innodb_flush_log_at_trx_commit = 2 innodb_log_buffer_size = 2M innodb_log_file_size = 4M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 innodb_file_per_table = 0 [mysqldump] quick max_allowed_packet = 2M [mysqld_safe] log-error=/data/3307/err_mysql_3307.err pid-file=/data/3307/mysqld.pid

3.3 初始化数据库表

初始化3306端口数据库
[root@mysql-multi ~]# cd /application/mysql/scripts/
[root@mysql-multi scripts]# ./mysql_install_db --basedir=/application/mysql --datadir=/data/3306/data --user=mysql
WARNING: The host 'mysql-multi' could not be looked up with resolveip.
This probably means that your libc libraries are not 100 % compatible
with this binary MySQL version. The MySQL daemon, mysqld, should work
normally with the exception that host name resolving will not work.
This means that you should use IP addresses instead of hostnames
when specifying MySQL privileges !
Installing MySQL system tables...
OK
Filling help tables...
OK
......此处省略

初始化3307端口数据库
[root@mysql-multi scripts]# ./mysql_install_db --basedir=/application/mysql --datadir=/data/3307/data --user=mysql
WARNING: The host 'mysql-multi' could not be looked up with resolveip.
This probably means that your libc libraries are not 100 % compatible
with this binary MySQL version. The MySQL daemon, mysqld, should work
normally with the exception that host name resolving will not work.
This means that you should use IP addresses instead of hostnames
when specifying MySQL privileges !
Installing MySQL system tables...
OK
Filling help tables...
OK
......此处省略

说明：一般情况下初始化数据库表时日志显示两个“OK”即表示初始化成功。
3.4 启动数据库多实例

[root@mysql-multi ~]# /data/3306/mysql start
Starting MySQL...
[root@mysql-multi ~]# /data/3307/mysql start
Starting MySQL...
[root@mysql-multi ~]# netstat -lntup|grep 330
tcp        0      0 0.0.0.0:3307                0.0.0.0:*                   LISTEN      28220/mysqld
tcp        0      0 0.0.0.0:3306                0.0.0.0:*                   LISTEN      26267/mysqld

说明：“mysql”是自己写的启动脚本就不贴出来了，mysql启动和停止的实质为：
mysql数据库启动命令：

# /application/mysql/bin/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &

mysql数据库停止命令：

# /application/mysql/bin/mysqladmin -u${mysql_user} -p${mysql_pwd} -S /data/${port}/mysql.sock shutdown

3.5 配置环境变量

[root@mysql-multi ~]# echo "export PATH=/application/mysql/bin:$PATH" >> /etc/profile
[root@mysql-multi ~]# tail -1 /etc/profile
export PATH=/application/mysql/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[root@mysql-multi ~]# . /etc/profile

3.6 登录数据库
登录3306数据库

[root@mysql-multi ~]# mysql -S /data/3306/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.32-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>

登录3307数据库

[root@mysql-multi ~]# mysql -S /data/3307/mysql.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.32 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>

说明：MySQL数据库在初始登录未设置登录用户名和密码，可以在登录数据库之后增加账户信息。至此配置MySQL数据库多实例完成。