mysqld_multi 多实例启动mysql

假设服务器之前有一个3306的实例在运行了，我们要再添加一个3316端口的实例。

直接编辑 /etc/my.cnf ，添加如下内容（红色部分是后添加的配置项）：
[client]
user= root
socket= /tmp/mysql.sock
port= 3306

[mysql]
prompt= '[\d] > '

[mysqld]
datadir=/bdata/data/nowdb2
socket= /tmp/mysql.sock
user=mysql
port= 3306
character-set-server= utf8
default_storage_engine= InnoDB
transaction_isolation = READ-COMMITTED
skip_name_resolve= ON
skip_external_locking
query_cache_type= OFF
query_cache_size= 0
server-id= 11
log-bin= mysql.bin
binlog_format= ROW
log_error= /bdata/data/nowdb2/error.log
innodb_file_per_table = ON

[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
log = /var/log/mysqld_multi.log

[mysqld2]
datadir=/data/mysql2
socket = /tmp/mysql2.sock
user=mysql
port = 3316
character-set-server = utf8
default_storage_engine = InnoDB
transaction_isolation =READ-COMMITTED
skip_name_resolve = ON
skip_external_locking
server-id = 106
log-bin = mysql-bin
slow_query_log = ON
slow_query_log_file = /data/mysql2/localhost_slow.log
long_query_time = 5
log_error = /data/mysql2/error.log
innodb_file_per_table = ON
innodb_flush_log_at_trx_commit = 1
sync_binlog = 1
innodb_support_xa = 1
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
symbolic-links=0
relay_log_info_repository = table
master_info_repository = table
relay_log_recovery = ON

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld.pid

[mysqldump]
quick
max_allowed_packet= 64M

初始化3316实例：
/usr/local/mysql/scripts/mysql_install_db--user=mysql --basedir=/usr/local/mysql/ --datadir=/data/mysql2/

启动3316实例：
mysqld_multireport
mysqld_multistart 3316 即可启动3316实例。

同样的方法，可以再配置其他的mysql实例。

关闭的话，建议使用mysqladmin 即可。

注意，mysqld_mulit和原来的mysqld的启动停止没有任何关系。我们可以关闭/etc/init.d/mysqld，对mysqld_multi启动的实例没有任何影响。