bitscn.com刚刚抽空做了一下mysql 的主主同步。把步骤写下来，至于会出现的什么问题，以后随时更新。这里我同步的数据库是test1、环境描述。主机：192.168.0.231（a）主机：192.168.0.232（b）mysql 版本为5.1.212、授权用户。a：mysql> grant replication slave,file on *.* to 'repl1'@'192.168.0.232' 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 'repl2'@'192.168.0.231' 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里面都开启二进制日志 。a：user = mysqllog-bin=mysql-binserver-id       = 1binlog-do-db=testbinlog-ignore-db=mysqlreplicate-do-db=testreplicate-ignore-db=mysqllog-slave-updatesslave-skip-errors=all skip-name-resolvesync_binlog=1auto_increment_increment=2auto_increment_offset=1b：user = mysqllog-bin=mysql-binserver-id       = 2binlog-do-db=testbinlog-ignore-db=mysqlreplicate-do-db=testreplicate-ignore-db=mysqllog-slave-updatesslave-skip-errors=all skip-name-resolvesync_binlog=1auto_increment_increment=2auto_increment_offset=2至于这些参数的说明具体看手册。红色的部分非常重要，如果一个master 挂掉的话，另外一个马上接管。紫红色的部分指的是服务器频繁的刷新日志。这个保证了在其中一台挂掉的话，日志刷新到另外一台。从而保证了数据的同步 。4、重新启动mysql服务器。在a和b上执行相同的步骤[root@localhost ~]# /usr/local/mysql/bin/mysqld_safe &[1] 4264[root@localhost ~]# 071213 14:53:20 mysqld_safe logging to '/usr/local/mysql/data/localhost.localdomain.err'./usr/local/mysql/bin/mysqld_safe: line 366: [: -eq: unary operator expected071213 14:53:20 mysqld_safe starting mysqld daemon with databases from /usr/local/mysql/data5、进入mysql的shell。a：mysql> flush tables with read lock/gquery ok, 0 rows affected (0.00 sec)mysql> show master status/g*************************** 1. row ***************************file: mysql-bin.000007position: 528binlog_do_db: testbinlog_ignore_db: mysql1 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.000004position: 595binlog_do_db: testbinlog_ignore_db: mysql1 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='192.168.0.232',    -> master_user='repl2',    -> 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='192.168.0.231',    -> master_user='repl1',    -> 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: 2user: replhost: 192.168.0.232:54475db: nullcommand: binlog dumptime: 1590state: has sent all binlog to slave; waiting for binlog to be updatedinfo: null*************************** 2. row ***************************id: 3user: system userhost: db: nullcommand: connecttime: 1350state: waiting for master to send eventinfo: null*************************** 3. row ***************************id: 4user: system userhost: db: nullcommand: connecttime: 1149state: has read all relay log; waiting for the slave i/o thread to update itinfo: null*************************** 4. row ***************************id: 5user: roothost: localhostdb: testcommand: querytime: 0state: nullinfo: show processlist4 rows in set (0.00 sec)b：mysql> show processlist/g*************************** 1. row ***************************id: 1user: system userhost: db: nullcommand: connecttime: 2130state: waiting for master to send eventinfo: null*************************** 2. row ***************************id: 2user: system userhost: db: nullcommand: connecttime: 1223state: has read all relay log; waiting for the slave i/o thread to update itinfo: null*************************** 3. row ***************************id: 4user: roothost: localhostdb: testcommand: querytime: 0state: nullinfo: show processlist*************************** 4. row ***************************id: 5user: repl2host: 192.168.0.231:50718db: nullcommand: binlog dumptime: 1398state: has sent all binlog to slave; waiting for binlog to be updatedinfo: null4 rows in set (0.00 sec)如果红色部分没有出现，检查data目录下的错误文件。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aa：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。bitscn.com