mysql的多实例有两种方式可以实现，两种方式各有利弊。
第一种是使用多个配置文件启动不同的进程来实现多实例，这种方式的优势逻辑简单，配置简单，缺点是管理起来不太方便。
第二种是通过官方自带的mysqld_multi使用单独的配置文件来实现多实例，这种方式定制每个实例的配置不太方面，优点是管理起来很方便，集中管理。
下面就分别来实战这两种多实例的安装和管理
环境介绍：
mysql 版本：5.1.50
操作系统：SUSE 11
mysql实例数：3个
实例占用端口分别为：3306、3307、3308
创建mysql用户
/usr/sbin/groupadd mysql
/usr/sbin/useradd -g mysql mysql
编译安装mysql
tar xzvf mysql-5.1.50.tar.gz cd mysql-5.1.50 ./configure '--prefix=/usr/local/mysql' '--with-charset=utf8' '--with-extra-charsets=complex' '--with-pthread' '--enable-thread-safe-client' '--with-ssl' '--with-client-ldflags=-all-static' '--with-mysqld-ldflags=-all-static' '--with-plugins=partition,innobase,blackhole,myisam,innodb_plugin,heap,archive' '--enable-shared' '--enable-assembler' make make install
初始化数据库
/usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/data/dbdata_3306 --user=mysql /usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/data/dbdata_3307 --user=mysql /usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/data/dbdata_3308 --user=mysql
创建配置文件
vim /data/dbdata_3306/my.cnf
3306的配置文件如下：
[client] port = 3306 socket = /data/dbdata_3306/mysql.sock [mysqld] datadir=/data/dbdata_3306/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3306 socket = /data/dbdata_3306/mysql.sock back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqldump] quick max_allowed_packet = 256M [mysql] no-auto-rehash prompt=\u@\d \R:\m> [myisamchk] key_buffer_size = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 8192
vim /data/dbdata_3307/my.cnf
3307的配置文件如下：
[client] port = 3307 socket = /data/dbdata_3307/mysql.sock [mysqld] datadir=/data/dbdata_3307/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3307 socket = /data/dbdata_3307/mysql.sock back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqldump] quick max_allowed_packet = 256M [mysql] no-auto-rehash prompt=\u@\d \R:\m> [myisamchk] key_buffer_size = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 8192
vim /data/dbdata_3308/my.cnf
3308的配置文件如下：
[client] port = 3308 socket = /data/dbdata_3308/mysql.sock [mysqld] datadir=/data/dbdata_3308/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3308 socket = /data/dbdata_3308/mysql.sock back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqldump] quick max_allowed_packet = 256M [mysql] no-auto-rehash prompt=\u@\d \R:\m> [myisamchk] key_buffer_size = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 8192
创建自动启动文件
vim /data/dbdata_3306/mysqld
3306的启动文件如下：
#!/bin/bash mysql_port=3306 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL... " /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/data/dbdata_${mysql_port}/my.cnf 2>&1 > /dev/null & } function_stop_mysql() { printf "Stoping MySQL... " /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /data/dbdata_${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL... " function_stop_mysql function_start_mysql } function_kill_mysql() { kill -9 $(ps -ef | grep 'bin/mysqld_safe' | grep ${mysql_port} | awk '{printf $2}') kill -9 $(ps -ef | grep 'libexec/mysqld' | grep ${mysql_port} | awk '{printf $2}') } case $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /data/dbdata_${mysql_port}/mysqld {start|stop|restart|kill}";; esac
vim /data/dbdata_3307/mysqld
3307的启动文件如下：
#!/bin/bash mysql_port=3307 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL... " /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/data/dbdata_${mysql_port}/my.cnf 2>&1 > /dev/null & } function_stop_mysql() { printf "Stoping MySQL... " /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /data/dbdata_${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL... " function_stop_mysql function_start_mysql } function_kill_mysql() { kill -9 $(ps -ef | grep 'bin/mysqld_safe' | grep ${mysql_port} | awk '{printf $2}') kill -9 $(ps -ef | grep 'libexec/mysqld' | grep ${mysql_port} | awk '{printf $2}') } case $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /data/dbdata_${mysql_port}/mysqld {start|stop|restart|kill}";; esac
vim /data/dbdata_3308/mysqld
3308的启动文件如下：
#!/bin/bash mysql_port=3308 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL... " /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/data/dbdata_${mysql_port}/my.cnf 2>&1 > /dev/null & } function_stop_mysql() { printf "Stoping MySQL... " /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /data/dbdata_${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL... " function_stop_mysql function_start_mysql } function_kill_mysql() { kill -9 $(ps -ef | grep 'bin/mysqld_safe' | grep ${mysql_port} | awk '{printf $2}') kill -9 $(ps -ef | grep 'libexec/mysqld' | grep ${mysql_port} | awk '{printf $2}') } case $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /data/dbdata_${mysql_port}/mysqld {start|stop|restart|kill}";; esac
启动3306、3307、3308的mysql
/data/dbdata_3306/mysqld start /data/dbdata_3307/mysqld start /data/dbdata_3308/mysqld start
更改原来密码（处于安全考虑，还需要删除系统中没有密码的帐号，这里省略了）：
/usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3306/mysql.sock /usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3307/mysql.sock /usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3308/mysql.sock
登录测试并创建关闭mysql的帐号权限，mysqld脚本要用到！
/usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges; /usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges; /usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges;
创建了admin帐号以后脚本的stop功能和restart功能就正常了！
更改环境变量
vim /etc/profile 添加下面一行内容 PATH=${PATH}:/usr/local/mysql/bin/ source /etc/profile
添加到自动启动
vim /etc/init.d/boot.local /data/dbdata_3306/mysqld start /data/dbdata_3307/mysqld start /data/dbdata_3308/mysqld start
如果是rhel或者centos系统的话自启动文件/etc/rc.local
管理的话，在本地都是采用 -S /data/dbdata_3308/mysql.sock，如果在远程可以通过不同的端口连接上去坐管理操作。其他的和单实例的管理没什么区别！
再来看第二种通过官方自带的mysqld_multi来实现多实例实战：
这里的mysql安装以及数据库的初始化和前面的步骤一样，就不再赘述。
mysqld_multi的配置
[mysqld_multi] mysqld = /usr/local/mysql/bin/mysqld_safe mysqladmin = /usr/local/mysql/bin/mysqladmin user = admin password = password [mysqld1] socket = /data/dbdata_3306/mysql.sock port = 3306 pid-file = /data/dbdata_3306/3306.pid datadir = /data/dbdata_3306 user = mysql skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqld2] socket = /data/dbdata_3307/mysql.sock port = 3307 pid-file = /data/dbdata_3307/3307.pid datadir = /data/dbdata_3307 user = mysql skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqld3] socket = /data/dbdata_3308/mysql.sock port = 3308 pid-file = /data/dbdata_3308/3308.pid datadir = /data/dbdata_3308 user = mysql skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 back_log = 50 max_connections = 300 max_connect_errors = 1000 table_open_cache = 2048 max_allowed_packet = 16M binlog_cache_size = 2M max_heap_table_size = 64M sort_buffer_size = 2M join_buffer_size = 2M thread_cache_size = 64 thread_concurrency = 8 query_cache_size = 64M query_cache_limit = 2M ft_min_word_len = 4 default-storage-engine = innodb thread_stack = 192K transaction_isolation = REPEATABLE-READ tmp_table_size = 64M log-bin=mysql-bin binlog_format=mixed slow_query_log long_query_time = 1 server-id = 1 key_buffer_size = 8M read_buffer_size = 2M read_rnd_buffer_size = 2M bulk_insert_buffer_size = 64M myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 myisam_recover innodb_additional_mem_pool_size = 16M innodb_buffer_pool_size = 200M innodb_data_file_path = ibdata1:10M:autoextend innodb_file_io_threads = 8 innodb_thread_concurrency = 16 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 16M innodb_log_file_size = 512M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 60 innodb_lock_wait_timeout = 120 [mysqldump] quick max_allowed_packet = 256M [mysql] no-auto-rehash prompt=\u@\d \R:\m> [myisamchk] key_buffer_size = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 8192
mysqld_multi启动
/usr/local/mysql/bin/mysqld_multi start 1 /usr/local/mysql/bin/mysqld_multi start 2 /usr/local/mysql/bin/mysqld_multi start 3
或者采用一条命令的形式：
/usr/local/mysql/bin/mysqld_multi start 1-3
更改原来密码（处于安全考虑，还需要删除系统中没有密码的帐号，这里省略了）：
/usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3306/mysql.sock /usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3307/mysql.sock /usr/local/mysql/bin/mysqladmin -uroot password 'password' -S /data/dbdata_3308/mysql.sock
登录测试并创建admin密码(停止mysql的时候需要使用到)
/usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges; /usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges; /usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3308/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges;
更改环境变量
vim /etc/profile PATH=${PATH}:/usr/local/mysql/bin/ source /etc/profile
添加到自动启动
vim /etc/init.d/boot.local /usr/local/mysql/bin/mysqld_multi start 1-3
如果是rhel或者centos系统的话自启动文件/etc/rc.local
管理的话，在本地都是采用 -S /data/dbdata_3308/mysql.sock，如果在远程可以通过不同的端口连接上去坐管理操作。其他的和单实例的管理没什么区别！
大家在管理多实例的话可以使用mysqlmanager实例管理器，管理器来会比较方面，限于篇幅，这里就不在多做介绍！