vim /etc/my.cnf
[client]
port= 3306
socket= /tmp/mysql.sock
default-character-set=utf8
[mysql]
default-character-set=utf8
[mysqld]
port= 3306
socket= /tmp/mysql.sock
basedir= /usr/local/mysql
datadir= /data/mysql
open_files_limit    = 3072
back_log = 103
max_connections = 800
max_connect_errors = 100000
table_open_cache = 512
external-locking = FALSE
max_allowed_packet = 32M
sort_buffer_size = 2M
join_buffer_size = 2M
thread_cache_size = 51
query_cache_size = 32M
tmp_table_size = 96M
max_heap_table_size = 96M
slow_query_log = 1
slow_query_log_file = /log/mysql/slow.log
log-error = /log/mysql/error.log
long_query_time = 1
server-id = 1
log-bin=master-bin
log_bin_index=master-bin.index
binlog-do-db=database_A  //需要同步的数据库。。 写字间的数据库名
log-bin = /log/mysql/mysql-bin
sync_binlog = 1
binlog_cache_size = 128M
max_binlog_cache_size = 512M
max_binlog_size = 1024M
expire_logs_days = 60
key_buffer_size = 32M
read_buffer_size = 1M
read_rnd_buffer_size = 16M
bulk_insert_buffer_size = 64M
character-set-server=utf8
default-storage-engine = InnoDB
binlog-format = row
innodb_buffer_pool_dump_at_shutdown = 1
innodb_buffer_pool_load_at_startup = 1
binlog_rows_query_log_events = 1
explicit_defaults_for_timestamp = 1
#log_slave_updates=1
#gtid_mode=on
#enforce_gtid_consistency=1
#innodb_write_io_threads = 8
#innodb_read_io_threads = 8
#innodb_thread_concurrency = 0
transaction_isolation = REPEATABLE-READ
innodb_additional_mem_pool_size = 16M
innodb_buffer_pool_size = 512M
#innodb_data_home_dir =
innodb_data_file_path = ibdata1:1024M:autoextend
innodb_flush_log_at_trx_commit = 1
innodb_log_buffer_size = 16M
innodb_log_file_size = 512M
innodb_log_files_in_group = 2
innodb_max_dirty_pages_pct = 50
innodb_file_per_table = 1
innodb_locks_unsafe_for_binlog = 0
wait_timeout = 14400
interactive_timeout = 14400
skip-name-resolve
[mysqldump]
quick
max_allowed_packet = 32M

[mysqld]
#
# 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
#
# 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
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
#禁用local_infile选项会降低攻击者通过SQL注入漏洞器读取敏感文件的能力
local-infile=0
server-id=2
relay-log=slave-relay-bin
relay-log-index=slave-relay-bin.index
log-bin=/var/lib/mysql/mysql-bin
binlog-format=ROW
# Recommended in standard MySQL setup
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

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

   mysql>GRANT REPLICATION SLAVE ON *.* to 'mysync'@'%' identified by 'q123456'; //一般不用root帐号

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000005 |   822410 | izone        |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.01 sec)

    //最优写法 master_log_pos默认值0
    change master to master_host='192.168.1.1', master_user='mysync', master_password='q123456', master_log_file='mysql-bin.000005', master_log_pos=0;

   mysql>change master to master_host='192.168.1.1',master_user='mysync',master_password='q123456',
         master_log_file='mysql-bin.000005',master_log_pos=822410;   //注意不要断开，822410数字前后无单引号。
   Mysql>start slave;    //启动从服务器复制功能

mysql>  show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.1
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000005
          Read_Master_Log_Pos: 822410
               Relay_Log_File: slave-relay-bin.000604
                Relay_Log_Pos: 4962
        Relay_Master_Log_File: mysql-bin.000005
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 822410
              Relay_Log_Space: 5298
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 1
                  Master_UUID: 4ba711e6-1e80-11eb-b46a-00163e002678
             Master_Info_File: /var/lib/mysql/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)

mysql>