MYSQL 的 MASTER到MASTER的主主循環同步

剛剛抽空作了一下MYSQL 的主主同步。
把步驟寫下來，至於會出現的什麼問題，之後隨時更新。這裏我同步的數據庫是TEST
一、環境描述。
   主機：192.168.0.231（A）
   主機：192.168.0.232（B）
   MYSQL 版本爲5.1.21
二、受權用戶。
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)
而後都中止MYSQL 服務器。

三、配置文件。
在兩個機器上的my.cnf裏面都開啓二進制日誌 。
A：
user = mysql
log-bin=mysql-bin
server-id       = 1
binlog-do-db=test
binlog-ignore-db=mysql
replicate-do-db=test
replicate-ignore-db=mysql
log-slave-updates
slave-skip-errors=all
sync_binlog=1
auto_increment_increment=2
auto_increment_offset=1

B：
user = mysql
log-bin=mysql-bin
server-id       = 2
binlog-do-db=test
binlog-ignore-db=mysql
replicate-do-db=test
replicate-ignore-db=mysql
log-slave-updates
slave-skip-errors=all
sync_binlog=1
auto_increment_increment=2
auto_increment_offset=2
至於這些參數的說明具體看手冊。
紅色的部分很是重要，若是一個MASTER 掛掉的話，另一個立刻接管。
紫紅色的部分指的是服務器頻繁的刷新日誌。這個保證了在其中一臺掛掉的話，日誌刷新到另一臺。從而保證了數據的同步 。
四、從新啓動MYSQL服務器。
在A和B上執行相同的步驟
[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 expected
071213 14:53:20 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data

五、進入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)
而後備份本身的數據，保持兩個機器的數據一致。
方法不少。完了後看下一步。
六、在各自機器上執行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)

七、查看各自機器上的IO進程和 SLAVE進程是否都開啓。
A：

mysql> show processlist\G
*************************** 1. row ***************************
     Id: 2
   User: repl
   Host: 192.168.0.232:54475
     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: 192.168.0.231:50718
     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)

若是紅色部分沒有出現，檢查DATA目錄下的錯誤文件。

八、釋放掉各自的鎖，而後進行插數據測試。
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)

插入以前兩個機器表的對比：
A：

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb     |
| t22            |
+----------------+
B：

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| t11_innodb     |
| t22            |
+----------------+
從A機器上進行插入
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)


如今來看B機器：

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)

如今反過來從B機器上插入數據：
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)
咱們來看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。如今兩個表互相爲MASTER。


多MASTER自增字段衝突的問題。
具體文章見：
[url]http://dev.mysql.com/tech-resources/articles/advanced-mysql-replication.html[/url]在郵件列表中看到有人討論在線同步與忽略庫與表的問題，具體看：[url]http://dev.mysql.com/doc/refman/5.1/en/replication-rules.html[/url]