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。

环境介绍：
mysql 版本：5.1.59
操作系统：Centos 5.5~5.6
mysql实例数：3个
实例占用端口分别为：3306、3307、3308

必要软件包

yum -y install ncurses-devel gcc gcc-c++ gcc-g77 autoconf automake zlib* fiex* libxml* libmcrypt* libtool-ltdl-devel* libtool make

创建mysql用户

/usr/sbin/groupadd mysql /usr/sbin/useradd -g mysql mysql -s /sbin/nologin

编译安装MySQL

cd /usr/local/src/mysql-5.1.59 ./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' # 接着执行编译 make &&　make install

初始化数据库

/usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data/3306/data --user=mysql /usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data/3307/data --user=mysql /usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data/3308/data --user=mysql

*为什么要初始化数据库? *
答:初始化的主要目的就是创建基础的数据库文件,例如生成MySQL库,表等.

授权数据库权限给mysql用户

setfacl -m u:mysql:rwx -R /usr/local/mysql setfacl -m d:u:mysql:rwx -R /usr/local/mysql

第一种使用多个配置文件启动多个不同进程的情况：

创建3个实例的配置文件

3306端口的配置文件

vim /usr/local/mysql/data/3306/my.cnf

[client] port = 3306 socket = /usr/local/mysql/data/3306/mysql.sock [mysqld] datadir = /usr/local/mysql/data/3306/data/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3306 socket = /usr/local/mysql/data/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 = 3306 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] log-error=/usr/local/mysql/data/3306/mysql_error3306.err pid-file=/usr/local/mysql/data/3306/mysqld.pid open-files-limit = 8192

3307端口的配置文件

vim /usr/local/mysql/data/3307/my.cnf

[client] port = 3307 socket = /usr/local/mysql/data/3307/mysql.sock [mysqld] datadir=/usr/local/mysql/data/3307/data/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3307 socket = /usr/local/mysql/data/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 = 3307 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] log-error=/usr/local/mysql/data/3307/mysql_error3307.err pid-file=/usr/local/mysql/data/3307/mysqld.pid open-files-limit = 8192

3308端口的配置文件

vim /usr/local/mysql/data/3308/my.cnf

[client] port = 3308 socket = /usr/local/mysql/data/3308/mysql.sock [mysqld] datadir=/usr/local/mysql/data/3308/data skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3308 socket = /usr/local/mysql/data/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 = 3308 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] log-error=/usr/local/mysql/data/3308/mysql_error3308.err pid-file=/usr/local/mysql/data/3308/mysqld.pid open-files-limit = 8192

创建自启动文件

vim /usr/local/mysql/data/3306/mysqld , 3306的启动文件

#!/bin/bash mysql_port=3306 mysql_username="admin" mysql_password="password" function_start_mysql(){ printf "Starting MySQL...\n" /bin/bash /usr/local/mysql/bin/mysqld_safe --defaults-file=/usr/local/mysql/data/${mysql_port}/my.cnf 2>&1 /dev/null & } function_stop_mysql(){ printf "Stoping MySQL...\n" /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /usr/local/mysql/data/${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL...\n" 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 $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /usr/local/mysql/data/${mysql_port}/mysqld {start|stop|restart|kill}";; esac

vim /usr/local/mysql/data/3307/mysqld , 3307的启动文件

#!/bin/bash mysql_port=3307 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL...\n" /bin/bash /usr/local/mysql/bin/mysqld_safe --defaults-file=/usr/local/mysql/data/${mysql_port}/my.cnf 2>&1 /dev/null & } function_stop_mysql() { printf "Stoping MySQL...\n" /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /usr/local/mysql/data/${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL...\n" 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 $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /usr/local/mysql/data/${mysql_port}/mysqld {start|stop|restart|kill}";; esac

vim /usr/local/mysql/data/3308/mysqld , 3308的启动文件

#!/bin/bash mysql_port=3308 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL...\n" /bin/bash /usr/local/mysql/bin/mysqld_safe --defaults-file=/usr/local/mysql/data/${mysql_port}/my.cnf 2>&1 /dev/null & } function_stop_mysql() { printf "Stoping MySQL...\n" /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /usr/local/mysql/data/${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL...\n" 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 $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /usr/local/mysql/data/${mysql_port}/mysqld {start|stop|restart|kill}";; esac

上面的三个启动文件中都包含了数据库密码等敏感信息,所以为了安全考虑,将权限改为只有root可以操作，执行下面的命令

find /usr/local/mysql/data -name 'mysqld'|xargs chmod 700 && find /usr/local/mysql/data -name 'mysqld'|xargs setfacl -b && find /usr/local/mysql/data -name 'mysqld'|xargs chown root.root

启动3306 3307 3308的MySQL

cd /usr/local/mysql/data && ./3306/mysqld start cd /usr/local/mysql/data && ./3307/mysqld start cd /usr/local/mysql/data && ./3308/mysqld start

启动报错
151016 06:36:48 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data/3307/data/
/usr/local/mysql/bin/mysqld: File './mysql-bin.~rec~' not found (Errcode: 28)
151016 6:36:48 [ERROR] MYSQL_BIN_LOG::open_purge_index_file failed to open register file.
151016 6:36:48 [ERROR] MYSQL_BIN_LOG::open_index_file failed to sync the index file.
151016 6:36:48 [ERROR] Aborting
151016 6:36:48 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete
151016 06:36:48 mysqld_safe mysqld from pid file /usr/local/mysql/data/3307/mysqld.pid ended

错误代码 (Errcode: 28)

产生错误原因(磁盘空间已满)

# df -Th 文件系统 类型 容量 已用 可用 已用% 挂载点 /dev/mapper/VolGroup00-LogVol00 ext3 8.9G 8.4G 0 100% / /dev/sda1 ext3 99M 12M 82M 13% /boot tmpfs tmpfs 1014M 0 1014M 0% /dev/shm

解决方案
释放硬盘空间，重新启动即可。

将mysql的bin加入到path中

ln -s /usr/local/mysql/bin/mysql /usr/local/sbin/mysql cd ~ #或者，把path添加到当前用户目录的bashrc中，如果需要全局设定，请修改`/etc/profile` vi .bashrc #加入以下内容 PATH=/usr/local/mysql/bin:$PATH source /etc/profile

修改默认root密码(指定sock文件)

mysqladmin -uroot password 'aaaaaa' -S /usr/local/mysql/data/3306/mysql.sock mysqladmin -uroot password 'aaaaaa' -S /usr/local/mysql/data/3307/mysql.sock mysqladmin -uroot password 'aaaaaa' -S /usr/local/mysql/data/3308/mysql.sock

##登录数据库增加进程关闭 admin(password) 账号

/usr/local/mysql/bin/mysql -uroot -ppassword -S /data/dbdata_3306/mysql.sock GRANT SHUTDOWN ON *.* TO 'admin'@'localhost' IDENTIFIED BY 'password'; flush privileges;

本机登录指定sock登录

mysql -uroot -paaaaaa -S /usr/local/mysql/data/3306/mysql.sock mysql -uroot -paaaaaa -S /usr/local/mysql/data/3307/mysql.sock mysql -uroot -paaaaaa -S /usr/local/mysql/data/3308/mysql.sock

后期增加一个实例的情况

初始化数据库

/usr/local/mysql/bin/mysql_install_db --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data/3309/data --user=mysql

新建一个默认配置文件

vim /usr/local/mysql/data/3309/my.cnf

[client] port = 3309 socket = /usr/local/mysql/data/3309/mysql.sock [mysqld] datadir = /usr/local/mysql/data/3309/data/ skip-name-resolve lower_case_table_names=1 innodb_file_per_table=1 port = 3309 socket = /usr/local/mysql/data/3309/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 = 3309 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] log-error=/usr/local/mysql/data/3309/mysql_error3309.err pid-file=/usr/local/mysql/data/3309/mysqld.pid open-files-limit = 8192

创建自启动文件

#!/bin/bash mysql_port=3309 mysql_username="admin" mysql_password="password" function_start_mysql() { printf "Starting MySQL...\n" /bin/bash /usr/local/mysql/bin/mysqld_safe --defaults-file=/usr/local/mysql/data/${mysql_port}/my.cnf 2>&1 > /dev/null & } function_stop_mysql() { printf "Stoping MySQL...\n" /usr/local/mysql/bin/mysqladmin -u ${mysql_username} -p${mysql_password} -S /usr/local/mysql/data/${mysql_port}/mysql.sock shutdown } function_restart_mysql() { printf "Restarting MySQL...\n" 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 $1 in start) function_start_mysql;; stop) function_stop_mysql;; kill) function_kill_mysql;; restart) function_stop_mysql function_start_mysql;; *) echo "Usage: /usr/local/mysql/data/${mysql_port}/mysqld {start|stop|restart|kill}";; esac

授权启动文件可执行

chmod a+x /usr/local/mysql/data/3309/mysqld

相关博文参考：
mysql多实例的配置和管理