mysql 启动方法
1.mysqld
mysqld  is the mysql server
mysqld reads options from the [mysqld] and [server] groups
we can invoke mysqld manually. this is usually not done except for debugging purposes.
if you invoke the server this way,error messages go to the terminal by default rather than to error log
--connection
 start
  ./libexec/mysqld --defaults-file=./my.cnf --user=mysql
  connect
  mysql --defaults-file=./my.cnf
  mysql -S /tmp/mysql.sock
 
   mysqld --defaults-file=my.cnf --user=mysql
2. mysqld_safe
    mysqld_safe reads all options from the [mysqld],[server],  and [mysqld_safe] sections in option
    files.For backward compatibility,is also reads [safe_mysqld] sections,although you should rename
    such sections to  [mysqld_safe] in mysql 5.1 installations
   
    mysqld_safe is a shell script that invokes mysqld.the script sets up the error log,and  then launches
    mysqld and monitors it .If mysqld terminates abnormally,mysql_sadr restarts it.
   
    connect
   -- start
     mysqld_safe  --defaults-file=./my.cnf --user=mysql &
     
   --connect
     mysqld -defaults-file=./my.cnf
     mysql -S /tmp/mysql.sock
     
 3.mysql.server
  mysql  distributions on unix include a script named mysql.server.it can be used on
  system such as linux and solaris that system v-style run diectories to start and stop
  system services.it is also used by max os x startup item for mysql
  
  $mysql_base/share/mysql/mysql.server and support-files/mysql.server
  
  mysql.server reads options from the [mysql.server] and [mysqld] sections of options files.
  for backward compatibility,it also reads [mysql_server] sections,although you should rename
  such sections to [mysql.server] when using mysql 5.1
  
  a shell script that invokes mysqld_safe

4.mysql_multi启动
 mysql_multi is designed to manage several mysqld processes that listen for connections on different Unix socket files and tcp/ip ports.
 it can start or stop servers ,report their current status.the mysql isntance manager is an alternative means of managing multiple
 servers
--hot to config
 1. mkdir $mysql_base/data2
 2.mysql_install_db --basedir=$mysql_base --datair=$mysql_base/data2 --user=mysql
 3 vi $mysql_base/my.cnf
 [mysqld_multi]
mysqld=/opt/mysql/bin/mysqld_safe
mysqladmin=/opt/mysql/bin/mysqladmin
user=test
password=test

[client]
port =3306
socket = /tmp/mysql.sock

[mysqld3306]

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.

--
# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
 log_bin=11g-lrep-bin

# These are commonly set, remove the # and set as required.
 basedir = /opt/mysql
 datadir =  /opt/mysql/data
 port = 3306
# server_id = .....
 socket =/tmp/mysql3306.sock
pid-file =/tmp/mysql3306.pid

# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
[mysqld3307]

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
 log_bin=11g-lrep-bin

# These are commonly set, remove the # and set as required.
 basedir = /opt/mysql
 datadir =  /opt/mysql/data2
 port = 3307
# server_id = .....
 socket =/tmp/mysql3307.sock
pid-file =/tmp/mysql3307.pid

# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
[mysqld3308]

# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
 log_bin=11g-lrep-bin

# These are commonly set, remove the # and set as required.
 basedir = /opt/mysql
 datadir =  /opt/mysql/data3
 port = 3308
# server_id = .....
 socket =/tmp/mysql3308.sock
pid-file =/tmp/mysql3308.pid
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

4.mysqld_multi --defaults-file=./my.cnf start 3306
5.mysql -u root -P3306 --protocol=tcp
 mysql -S /tmp/mysql3306.sock
 
 日志位置
/opt/mysql/share/mysqld_multi.log

6.grant shutdown on *.* to 'test'@localhost identified by 'test' with grant option;
 
 show grants for test@localhost;
 mysql> show grants for root@localhost;
+---------------------------------------------------------------------+
| Grants for root@localhost                                           |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION        |
+---------------------------------------------------------------------+
2 rows in set (0.00 sec)

7.mysqld_multi --defaults-file=./my.cnf stop 3306
  mysqld_multi --defaults-file=my.cnf stop 3307-3308

--连接mysql
    communication protocols
    protocol     types of connections             supported
    tcp/ip