1、环境描述。
主机：103.241.49.137（A）
主机：103.240.182.191（B）
MYSQL 版本为5.1.11
2、授权用户。(本人比较懒，直接用的root 跳过这一步)
A：
mysql> grant replication slave,file on *.* to 'backup_251'@'103.240.182.191' identified
by '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
B：
mysql> grant replication slave,file on *.* to 'backup_167'@'103.241.49.137' identified
by '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
然后都停止MYSQL 服务器。
3、配置文件。
在两个机器上的my.cnf,在windows下面就是my.ini文件了 里面都开启二进制日志 。
找到[mysqld]这个结点，在下面增加以下内容
vi /etc/my.cnf
A：
user = mysql
log-bin=mysql-bin
server-id = 1
binlog-do-db=test (需要同步的库，如果要同步整个数据库，就把这句去掉)
binlog-ignore-db=mysql (不需要同步的库)
replicate-do-db=test
//log-slave-updates 为了让slave也能充当master，写relay-log的时候也会写到bin-log
replicate-ignore-db=mysql
slave-skip-errors=all #出现错误后忽略，如果不加这个，出现任何错误，同步进程会终止
//master-connect-retry=60 断点重新连接时间
sync_binlog=1
auto_increment_increment=2 (因为是双向，自动增加的id会有冲突，把步长改为2 初始设为1)
auto_increment_offset=1
///////////////////////////////////////////
server-id = 1
log-bin=/tmp/logbin/mysql-bin
binlog-do-db =sixfj
binlog-ignore-db=mysql
replicate-do-db=sixfj
replicate-ignore-db=mysql
slave-skip-errors=all
sync_binlog=1
auto_increment_increment=2
auto_increment_offset=1
// linux关闭MySQL的命令
/usr/local/mysql/bin/mysqladmin -uroot -p shutdown
// linux启动MySQL的命令
/usr/local/mysql/bin/mysqld_safe &
/usr/local/mysql/bin/mysql -uroot -pgdczxw2008
grant replication slave on *.* to czxync@'103.240.182.191' identified by 'aa12345q';
B：
user = mysql
log-bin=mysql-bin
server-id = 2
binlog-do-db=test (需要同步的库，如果要同步整个数据库，就把这句去掉)
binlog-ignore-db=mysql (不需要同步的库)
replicate-do-db=test
replicate-ignore-db=mysql
slave-skip-errors=all
sync_binlog=1
auto_increment_increment=2 (因为是双向，自动增加的id会有冲突，把步长改为2 初始设为2)
auto_increment_offset=2
///////////////////////////////////
server-id = 3
log-bin=/tmp/logbin/mysql-bin
binlog-do-db =sixfj
binlog-ignore-db=mysql
replicate-do-db=sixfj
replicate-ignore-db=mysql
slave-skip-errors=all
sync_binlog=1
auto_increment_increment=2
auto_increment_offset=2
至于这些参数的说明具体看手册。
4、重新启动MYSQL服务器。
mysql>grant replication slave on *.* to czxync@'103.241.49.137' identified by 'aa12345q';
5、进入MYSQL的SHELL。
A：
mysql> flush tables with read lock/G
Query OK, 0 rows affected (0.00 sec)
mysql> show master status/G
*************************** 1. row ***************************
File: mysql-bin.000007
Position: 528
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
1 row in set (0.00 sec)
B：
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
mysql> show master status/G
*************************** 1. row ***************************
File: mysql-bin.000004
Position: 595
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
1 row in set (0.00 sec)
然后备份自己的数据，保持两个机器的数据一致。
方法很多。完了后看下一步。
6、在各自机器上执行CHANGE MASTER TO命令。
A：
mysql> change master to
-> master_host='103.240.182.191',
-> master_user='backup_251',
-> master_password='123456',
-> master_log_file='mysql-bin.000004',
-> master_log_pos=595;
Query OK, 0 rows affected (0.01 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
B：
mysql> change master to
-> master_host='103.241.49.137',
-> master_user='backup_167',
-> master_password='123456',
-> master_log_file='mysql-bin.000007',
-> master_log_pos=528;
Query OK, 0 rows affected (0.01 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
7、查看各自机器上的IO进程和 SLAVE进程是否都开启。
A：
mysql> show processlist/G;
*************************** 1. row ***************************
Id: 2
User: repl
Host: 103.240.182.191:54475
db: NULL
Command: Binlog Dump
Time: 1590
State: Has sent all binlog to slave; waiting for binlog to be updated
Info: NULL
*************************** 2. row ***************************
Id: 3
User: system user
Host:
db: NULL
Command: Connect
Time: 1350
State: Waiting for master to send event
Info: NULL
*************************** 3. row ***************************
Id: 4
User: system user
Host:
db: NULL
Command: Connect
Time: 1149
State: Has read all relay log; waiting for the slave I/O thread to update it
Info: NULL
*************************** 4. row ***************************
Id: 5
User: root
Host: localhost
db: test
Command: Query
Time: 0
State: NULL
Info: show processlist
4 rows in set (0.00 sec)
B：
mysql> show processlist/G
*************************** 1. row ***************************
Id: 1
User: system user
Host:
db: NULL
Command: Connect
Time: 2130
State: Waiting for master to send event
Info: NULL
*************************** 2. row ***************************
Id: 2
User: system user
Host:
db: NULL
Command: Connect
Time: 1223
State: Has read all relay log; waiting for the slave I/O thread to update it
Info: NULL
*************************** 3. row ***************************
Id: 4
User: root
Host: localhost
db: test
Command: Query
Time: 0
State: NULL
Info: show processlist
*************************** 4. row ***************************
Id: 5
User: repl2
Host: 103.241.49.137:50718
db: NULL
Command: Binlog Dump
Time: 1398
State: Has sent all binlog to slave; waiting for binlog to be updated
Info: NULL
4 rows in set (0.00 sec)
8、释放掉各自的锁，然后进行插数据测试。
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
插入之前两个机器表的对比：
A：
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb |
| t22 |
+----------------+
B：
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb |
| t22 |
+----------------+
从A机器上进行插入
A：
mysql> create table t11_replicas
-> (id int not null auto_increment primary key,
-> str varchar(255) not null) engine myisam;
Query OK, 0 rows affected (0.01 sec)
mysql> insert into t11_replicas(str) values
-> ('This is a master to master test table');
Query OK, 1 row affected (0.01 sec)
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb |
| t11_replicas |
| t22 |
+----------------+
3 rows in set (0.00 sec)
mysql> select * from t11_replicas;
+----+---------------------------------------+
| id | str |
+----+---------------------------------------+
| 1 | This is a master to master test table |
+----+---------------------------------------+
1 row in set (0.00 sec)
现在来看B机器：
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb |
| t11_replicas |
| t22 |
+----------------+
3 rows in set (0.00 sec)
mysql> select * from t11_replicas;
+----+---------------------------------------+
| id | str |
+----+---------------------------------------+
| 1 | This is a master to master test table |
+----+---------------------------------------+
1 row in set (0.00 sec)
现在反过来从B机器上插入数据：
B：
mysql> insert into t11_replicas(str) values('This is a test 2');
Query OK, 1 row affected (0.00 sec)
mysql> select * from t11_replicas;
+----+---------------------------------------+
| id | str |
+----+---------------------------------------+
| 1 | This is a master to master test table |
| 2 | This is a test 2 |
+----+---------------------------------------+
2 rows in set (0.00 sec)
我们来看A
A：
mysql> select * from t11_replicas;
+----+---------------------------------------+
| id | str |
+----+---------------------------------------+
| 1 | This is a master to master test table |
| 2 | This is a test 2 |
+----+---------------------------------------+
2 rows in set (0.00 sec)
好了。现在两个表互相为MASTER。