基礎知識：
需求：
最初只有主數據庫，這樣即使有數據備份，對業務保證也不夠高（業務不大，不需要做主主）。所以新增一臺數據庫備用服務器，做主從複製。
準備：
在master數據庫服務器的操作
添加用於複製的用戶
添加用於複製的用戶
grant replication client,replication slave on *.* to 'angus'@'%.%.%.%' identified by 'password';
修改server id （只要主從server id不一樣就行，可以再從服務器該。）
開啓binary logging（一般都開啓過）
修改server id
開啓relay-log
開啓binary logging（主從切換 做準備）
操作：
1，在從服務器上配置好數據庫，最後和主數據庫是一個版本。
1，在從服務器上配置好數據庫，最後和主數據庫是一個版本。
2，sed -i '/^server-id/s#1#2#g' /etc/my.cnf
3，開啓relay-log 在/etc/my.cnf 的[mysqld]區域添加下面代碼
relay-log=relay-bin
relay-log=relay-bin.index
relay-log=relay-bin.index
sed -i '/^server-id/a\relay-log=relay-bin\nrelay-log=relay-bin.index' /etc/my.cnf
4，對主數據進行一次完全備份
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.66 Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.02 sec)
mysql> quit
Bye
[root@localhost ~]# mysqldump -hlocalhost -uroot -p --all-databases --single-transaction --master-data=2 > /root/all.sql
Enter password:
[root@localhost ~]# ls
all.sql anaconda-ks.cfg install.log install.log.syslog Music Pictures Public Templates Videos yum.sh
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.66-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@localhost ~]#
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.1.66 Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.02 sec)
mysql> quit
Bye
[root@localhost ~]# mysqldump -hlocalhost -uroot -p --all-databases --single-transaction --master-data=2 > /root/all.sql
Enter password:
[root@localhost ~]# ls
all.sql anaconda-ks.cfg install.log install.log.syslog Music Pictures Public Templates Videos yum.sh
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.66-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@localhost ~]#
把all.sql 傳送到從服務器上，並導入到mysql服務器上。
[root@localhost ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
[root@localhost ~]# mysql < all.sql
[root@localhost ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
[root@localhost ~]# mysql < all.sql
[root@localhost ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
[root@localhost ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.1.61-log Source distribution
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.1.61-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| info.angus.com |
| know.angus.com |
| mysql |
| test |
+--------------------+
7 rows in set (0.02 sec)
+--------------------+
| Database |
+--------------------+
| information_schema |
| info.angus.com |
| know.angus.com |
| mysql |
| test |
+--------------------+
7 rows in set (0.02 sec)
設置從數據庫複製數據的主數據（MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=342這些內容可以在less all.sql中找到-- CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=106;）
mysql> change master to master_host='x.x.x.x',master_user='angus',master_password='password',MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=342;
Query OK, 0 rows affected (0.03 sec)
mysql> START SLAVE;
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW SLAVE STATUS\G
Query OK, 0 rows affected (0.03 sec)
mysql> START SLAVE;
Query OK, 0 rows affected (0.01 sec)
mysql> SHOW SLAVE STATUS\G
如果沒有報錯，此時主從複製基本上都成功了。
主從切換：
由於各種原因，住數據庫掛了，並且段時間內無法修復，爲了不影響，線上服務，需要及時做主從切換。
[root@localhost ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.1.61-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> STOP SLAVE IO_THREAD; //確保從服務器已經處理了中繼日誌中的所有語句
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW PROCESSLIST; //檢查SHOW PROCESSLIST語句的輸出，直到你看到Has read all relay log
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
| 5 | system user | | NULL | Connect | 2349 | Has read all relay log; waiting for the slave I/O thread to update it | NULL |
| 8 | root | localhost | NULL | Query | 0 | NULL | SHOW PROCESSLIST |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
2 rows in set (0.00 sec)
mysql> STOP SLAVE;
Query OK, 0 rows affected (0.00 sec)
mysql> RESET MASTER;
Query OK, 0 rows affected (0.08 sec)
mysql> RESET SLAVE;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye
[root@localhost ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.1.61-log Source distribution
Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> STOP SLAVE IO_THREAD; //確保從服務器已經處理了中繼日誌中的所有語句
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW PROCESSLIST; //檢查SHOW PROCESSLIST語句的輸出，直到你看到Has read all relay log
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
| 5 | system user | | NULL | Connect | 2349 | Has read all relay log; waiting for the slave I/O thread to update it | NULL |
| 8 | root | localhost | NULL | Query | 0 | NULL | SHOW PROCESSLIST |
+----+-------------+-----------+------+---------+------+-----------------------------------------------------------------------+------------------+
2 rows in set (0.00 sec)
mysql> STOP SLAVE;
Query OK, 0 rows affected (0.00 sec)
mysql> RESET MASTER;
Query OK, 0 rows affected (0.08 sec)
mysql> RESET SLAVE;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye
[root@localhost ~]# /etc/init.d/mysqld restart
Stopping mysqld: [ OK ]
Starting mysqld: [ OK ]
此時 從服務器升級爲主服務器，一般情況下從服務的性能沒有主服務器的好，所以當主服務器正常後，首先進入服務找到故障前一刻master狀態。
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000002 | 106 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.01 sec)
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000002 | 106 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.01 sec)
然後讓原來的主服務器做從服務器（開啓中繼日誌），複製數據（首先的有執行復制權限的用戶如angus1）
mysql> change master to master_host='x.x.x.x',master_user='angus1',master_password='password',MASTER_LOG_FILE='mysql-bin.000002 , MASTER_LOG_POS=106;
Query OK, 0 rows affected (0.03 sec)
Query OK, 0 rows affected (0.03 sec)
等所有數據複製完成後，再做次主從切換。
附：
mysql對數據庫過濾：有兩種形式，一般使用下面一種。
mysql對數據庫過濾：有兩種形式，一般使用下面一種。
複製過濾器
binlog-do-db = mydb 表示只限制與mydb的修改操作纔會記錄到二進制日誌
binlog-inore-db = mydb
中繼日誌 過濾
replicate-do-db = mydb
replicate-ignore-db = mydb
replicate-do-table = table
replicate-ignore-table = table
replicate-wild-do-table = db_pattern.tb1_pattern
replicate-wild-ignore-table = db_pattern.tb1_pattern
binlog-do-db = mydb 表示只限制與mydb的修改操作纔會記錄到二進制日誌
binlog-inore-db = mydb
中繼日誌 過濾
replicate-do-db = mydb
replicate-ignore-db = mydb
replicate-do-table = table
replicate-ignore-table = table
replicate-wild-do-table = db_pattern.tb1_pattern
replicate-wild-ignore-table = db_pattern.tb1_pattern