主从同步的特点:
逻辑的
异步的
主从同步的作用
1.备份
2.读写分离
主从同步的步骤
- 准备环境
1, mysql版本一致 5.5以上
2, 主从数据库一致
主库master修改
1.修改my.cnf
# 打开主库binlog
log-bin = mysql-bin
# 主数据库端ID号(区别于从库)
server-id = 1
2.重启mysql,创建用于同步的账号
grant replication slave on *.* to \'rep\'@\'%\' identified by \'123456\';
flush privileges;
查看master状态
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000009 | 196 | | |
+------------------+----------+--------------+------------------+
1 row in set
注：执行完这个步骤后不要再操作主数据库了，防止主数据库状态值变化
从库slave的修改
1.修改mysql配置
# 从数据库端ID号
server-id =2
执行同步命令
# 执行同步命令，设置主数据库ip，同步帐号密码，同步位置
mysql>change master to master_host=\'192.168.1.2\',master_user=\'rep\',master_password=\'123456\',master_log_file=\'mysql-bin.000009\',master_log_pos=196;
# 开启同步功能
mysql>start slave;
检查从库的状态
mysql> show slave status\\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.2
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000009
Read_Master_Log_Pos: 196
Relay_Log_File: vicky-relay-bin.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000009
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
注：Slave_IO_Running及Slave_SQL_Running进程必须正常运行，即YES状态，否则说明同步失败。
到这里，主从数据库设置工作已经完成，自己可以新建数据库和表，插入和修改数据，测试一下是否成功
其他可能用到的相关参数
master端
# 不同步哪些数据库
binlog-ignore-db = mysql
binlog-ignore-db = test
binlog-ignore-db = information_schema
# 只同步哪些数据库，除此之外，其他不同步
binlog-do-db = game
# 日志保留时间
expire_logs_days = 10
# 控制binlog的写入频率。每执行多少次事务写入一次
# 这个参数性能消耗很大，但可减小MySQL崩溃造成的损失
sync_binlog = 5
# 日志格式，建议mixed
# statement 保存SQL语句
# row 保存影响记录数据
# mixed 前面两种的结合
binlog_format = mixed
slave端
# 停止主从同步
mysql> stop slave;
# 连接断开时，重新连接超时时间
mysql> change master to master_connect_retry=50;
# 开启主从同步
mysql> start slave;
以上连接超时设置，类似方式可用于设置主数据库ip，同步帐号密码，同步位置
拓展阅读：MySQL日志格式 binlog_format
binlog的常用功能
| 常用功能 | 语句 |
|---|---|
| 查看bin-log开关 | show variables like "%log_bin%"; |
| 查看log格式 | show variables like "%format%"; |
| 查看binlog | show binary log; |
| 刷新binlog | reset master; |
| - | - |
| 查看版本 | \\s; |
| 查看引擎 | show variables like "%engine%"; |
| 查看字符集 | show variables like "%char%"; |
| 查看slowlog | show variables like "%slow%"; |
| - | - |
| 建库 | create database student; |
| 建表 | create table stu(id int,name char(40)); |
| 插入数据 | insert into stu values (1,\'maotai\'); |
| 查看表字段 | desc stu; |
| 查看建表语句 | show create table stu; |
| 查询 | select user,host from mysql.user; |
| 查看错误日志 | show variables like \'%error%\'; |
| 最大连接数(151默认) | show variables like "%max_conn%"; |
| 在mysql>执行sh命令 | system ls /opt |
- 查看logbin开关
mysql> show variables like "%log_bin%";
+---------------------------------+---------------------------------------+
| Variable_name | Value |
+---------------------------------+---------------------------------------+
| log_bin | ON |
| log_bin_basename | /usr/local/mysql/data/mysql-bin |
| log_bin_index | /usr/local/mysql/data/mysql-bin.index |
| log_bin_trust_function_creators | OFF |
| log_bin_use_v1_row_events | OFF |
| sql_log_bin | ON |
+---------------------------------+---------------------------------------+
6 rows in set (0.01 sec)
- 查看日志格式
mysql> show variables like "%format%";
+--------------------------+-------------------+
| Variable_name | Value |
+--------------------------+-------------------+
| binlog_format | STATEMENT |
| date_format | %Y-%m-%d |
| datetime_format | %Y-%m-%d %H:%i:%s |
| default_week_format | 0 |
| innodb_file_format | Antelope |
| innodb_file_format_check | ON |
| innodb_file_format_max | Antelope |
| time_format | %H:%i:%s |
+--------------------------+-------------------+
8 rows in set (0.00 sec)
- 查看二进制日志
mysql> show binary log;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near \'log\' at line 1
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 120 |
+------------------+-----------+
1 row in set (0.00 sec)
- 切割日志
mysql> reset master;
Query OK, 0 rows affected (0.09 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 120 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)