MySQL主從同步原理和部署
一.主從的作用：
1.可以當做一種備份方式
2.用來實現讀寫分離，緩解一個數據庫的壓力
二.MySQL主從備份原理
master 上提供binlog ,
slave 通過 I/O線程從 master拿取 binlog,並復制到slave的中繼日誌中
slave 通過 SQL線程從 slave的中繼日誌中讀取binlog ,然後解析到slave中
部署主從環境：主服務器：192.168.1.110（編譯好的MySQL5.1版本的數據庫）
從服務器：192.168.1.120（編譯好的MySQL5.1版本的數據庫）
（溫馨提示：主和從數據庫版本必須是一樣。或者主庫的數據庫版本必須比從庫高,不然會導致很多故障的發生。）
三：生產環境應用MySQL主從同步場景：
1. 一般用主庫做為提供業務用戶寫操作（比如：在互聯網上寫一條微博，這時候就會寫到mysql數據庫的主庫中）
2. 一般用從庫做為提供業務用戶讀操作（比如：在互聯網上，我想看一條微博，這時候裏面提供數據就是MySQL數據庫的從庫中。）
(1)在主服務器（192.168.1.110）上操作。
[root@Andy ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:5E:6F:A7
inet addr:192.168.1.110 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe5e:6fa7/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:141354 errors:0 dropped:0 overruns:0 frame:0
TX packets:140807 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:142083379 (135.5 MiB) TX bytes:17815696 (16.9 MiB)
Interrupt:193 Base address:0x2000
[root@Andy ~]# vi /etc/my.cnf
[mysqld]在mysqld下添加以上兩行。
server-id = 1
log-bin= Andy -bin
[root@Andy ~]# /etc/init.d/mysqld restart
Shutting down MySQL[ OK ]
Starting MySQL.[ OK ]
[root@Andy ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.44 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show master status;
+--------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+--------------------+----------+--------------+------------------+
| Andy-bin.000001 | 106 | | |
+--------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
請記住：File裏的Andy-bin.000001 和 Position 106 。
Mysql> grant replication slave on *.* to 'python'@'192.168.1.%' identified by '123456';
mysql> quit
Bye
在從服務器（192.168.1.120）上操作：
[root@Andy ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:2B:8E:D2
inet addr:192.168.1.120 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe2b:8ed2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:180290 errors:0 dropped:0 overruns:0 frame:0
TX packets:146169 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:223411069 (213.0 MiB) TX bytes:15504427 (14.7 MiB)
Interrupt:193 Base address:0x2000
[root@Andy ~]# vi /etc/my.cnf
把server-id = 1 改為：server-id = 2
然後重啟Mysql服務：[root@Andy ~]# /etc/init.d/mysqld restart
Shutting down MySQL........[ OK ]
Starting MySQL.[ OK ]
[root@Andy ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.44 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> CHANGE MASTER TO MASTER_HOST='192.168.1.110', MASTER_PORT=3306, MASTER_USER='python', MASTER_PASSWORD='123456', MASTER_LOG_FILE=' Andy-bin .000001', MASTER_LOG_POS=106;
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.110
Master_User: python
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: Andy-bin.000001
Read_Master_Log_Pos: 106
Relay_Log_File: Andy-relay-bin.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: Andy-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 106
Relay_Log_Space: 410
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.01 sec)
如果： Slave_IO_Running: Yes （主從I/O正確）
Slave_SQL_Running: Yes（主從進程正確）
（3）測試主從數據同步：在主服務器（192.168.1.110）上操作：
[root@Andy ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:5E:6F:A7
inet addr:192.168.1.110 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe5e:6fa7/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:142562 errors:0 dropped:0 overruns:0 frame:0
TX packets:141697 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:142192520 (135.6 MiB) TX bytes:17915582 (17.0 MiB)
Interrupt:193 Base address:0x2000
[root@Andy ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.1.44-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> create database Andy ;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| Andy |
| mysql |
| test |
+--------------------+
4 rows in set (0.00 sec)
mysql> use Andy ;
Database changed
mysql> create table Andy (id int(3),name char(10));
Query OK, 0 rows affected (0.01 sec)
mysql> insert into Andy values (001,'imysql');
Query OK, 1 row affected (0.00 sec)
(提示：我剛剛在主服務器上創建了一個Andy 數據庫和表，我現在在從服務器上查看結果，是否有Andy數據庫和表？)
在從服務器（192.168.1.120）上操作：
[root@Andy ~]# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:0C:29:2B:8E:D2
inet addr:192.168.1.120 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe2b:8ed2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:180884 errors:0 dropped:0 overruns:0 frame:0
TX packets:146585 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:223461833 (213.1 MiB) TX bytes:15555296 (14.8 MiB)
Interrupt:193 Base address:0x2000
[root@Andy ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.44 Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| Andy |
| mysql |
| test |
+--------------------+
4 rows in set (0.00 sec)
mysql> use Andy ;
Database changed
mysql> select * from Andy ;
+------+--------+
| id | name |
+------+--------+
| 1 | imysql |
+------+--------+
1 row in set (0.00 sec)