MySQL主從介紹
- MySQL主從又叫做Replication、AB複製。簡單講就是A和B兩臺機器做主從後，在A上寫數據，另外一臺B也會跟着寫數據，兩者數據實時同步的。
- MySQL主從是基於binlog的，主上須開啓binlog才能進行主從。
- 主從過程大致有3個步驟:
- 主將更改操作記錄到binlog裏;
- 從將主的binlog事件(sql語句)同步到從本機上並記錄在relaylog裏;
- 從根據relaylog裏面的sql語句按順序執行;
- 主上有一個log dump線程，用來和從的I/O線程傳遞binlog;
- 從上有兩個線程，其中I/O線程用來同步主的binlog並生成relaylog，另外一個SQL線程用來把relaylog裏面的sql語句落地;
準備工作
1. 準備AB兩臺機器都安裝好mysql，mysql安裝詳情請查看如下鏈接。
https://blog.51cto.com/taoxie/2050826
配置主 （A機器）
1.修改my.cnf配置文件
[root@gary-tao mysql]# vi /etc/my.cnf
增加配置內容：
server-id=100
log_bin=aminglinux1
[root@gary-tao mysql]# /etc/init.d/mysqld restart //更改完配置重啓mysql
Shutting down MySQL.... SUCCESS!
Starting MySQL.. SUCCESS!
[root@gary-tao mysql]# cd /data/mysql/
[root@gary-tao mysql]# ls -lt //重啓完成後目錄下有生成新的文件
總用量 110648
-rw-rw---- 1 mysql mysql 50331648 1月 19 19:44 ib_logfile0
-rw-rw---- 1 mysql mysql 12582912 1月 19 19:44 ibdata1
-rw-rw---- 1 mysql mysql 24867 1月 19 19:44 gary-tao.err
-rw-rw---- 1 mysql mysql 6 1月 19 19:44 gary-tao.pid
-rw-rw---- 1 mysql mysql 120 1月 19 19:44 aminglinux1.000001
-rw-rw---- 1 mysql mysql 21 1月 19 19:44 aminglinux1.index
drwx------ 2 mysql mysql 324 1月 18 13:42 zrlog
drwx------ 2 mysql mysql 4096 1月 15 19:25 mysql2
-rw-rw---- 1 mysql mysql 56 12月 27 19:40 auto.cnf
drwx------ 2 mysql mysql 4096 12月 27 19:32 mysql
drwx------ 2 mysql mysql 4096 12月 27 19:32 performance_schema
-rw-rw---- 1 mysql mysql 50331648 12月 27 19:32 ib_logfile1
drwx------ 2 mysql mysql 6 12月 27 19:32 test
修改配置示例圖
2.準備一個數據庫做演示使用
[root@gary-tao mysql]# mysqldump -uroot -pszyino-123 zrlog > /tmp/zrlog.sql //備份之前舊的數據庫zrlog
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao mysql]# du -sh /tmp/zrlog.sql //查看數據庫大小
12K /tmp/zrlog.sql
[root@gary-tao mysql]# mysql -uroot -pszyino-123 -e "create database aming" //創建一個新的數據庫
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao mysql]# mysql -uroot -pszyino-123 aming < /tmp/zrlog.sql //恢復之前備份的zrlog庫
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao mysql]# ls -lt
總用量 225344
-rw-rw---- 1 mysql mysql 50331648 1月 19 20:45 ib_logfile0
-rw-rw---- 1 mysql mysql 79691776 1月 19 20:45 ibdata1
-rw-rw---- 1 mysql mysql 12097 1月 19 20:45 aminglinux1.000001
drwx------ 2 mysql mysql 324 1月 19 20:45 aming
-rw-rw---- 1 mysql mysql 24867 1月 19 19:44 gary-tao.err
-rw-rw---- 1 mysql mysql 6 1月 19 19:44 gary-tao.pid
-rw-rw---- 1 mysql mysql 21 1月 19 19:44 aminglinux1.index
drwx------ 2 mysql mysql 324 1月 18 13:42 zrlog
drwx------ 2 mysql mysql 4096 1月 15 19:25 mysql2
-rw-rw---- 1 mysql mysql 56 12月 27 19:40 auto.cnf
drwx------ 2 mysql mysql 4096 12月 27 19:32 mysql
drwx------ 2 mysql mysql 4096 12月 27 19:32 performance_schema
-rw-rw---- 1 mysql mysql 50331648 12月 27 19:32 ib_logfile1
drwx------ 2 mysql mysql 6 12月 27 19:32 test
3.創建用作主從相互同步數據的用戶
[root@gary-tao mysql]# mysql -uroot -pszyino-123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1535
Server version: 5.6.35-log MySQL Community Server (GPL)
Copyright (c) 2000, 2016, 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> grant replication slave on *.* to 'repl'@'172.16.111.110' identified by 'szyino-123'; //創建同步賬戶
#這裏的repl是爲從（slave）端設置的訪問主（master）端的用戶，也就是要完成主從複製的用戶，密碼爲szyino-123，這裏的127.16.111.110爲slave（從）的ip。
Query OK, 0 rows affected (0.00 sec)
mysql> flush tables with read lock; //鎖定數據庫寫操作
Query OK, 0 rows affected (0.02 sec)
mysql> show master status; //查看master的狀態，這些數據是要記錄的，一會在slave端用到。
+--------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+--------------------+----------+--------------+------------------+-------------------+
| aminglinux1.000001 | 12777 | | | |
+--------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql> quit
Bye
[root@gary-tao mysql]# ls //爲了更加與生產環境一樣，把所有的庫都做一個備份，包括aming\mysql2\zrlog,mysql庫不需要同步。
aming aminglinux1.index gary-tao.err ibdata1 ib_logfile1 mysql2 test
aminglinux1.000001 auto.cnf gary-tao.pid ib_logfile0 mysql performance_schema zrlog
[root@gary-tao mysql]# ls /tmp/zrlog.sql
/tmp/zrlog.sql
[root@gary-tao mysql]# mysqldump -uroot -pszyino-123 mysql2 > /tmp/my2.sql
Warning: Using a password on the command line interface can be insecure.
[root@gary-tao mysql]# ls /tmp/*sql
/tmp/my2.sql /tmp/zrlog.sql
配置從（B機器）
1.修改slave的配置文件my.cnf
[root@gary mysql]# vi /etc/my.cnf
增加配置如下內容：
server-id=110 //設置成和master（主）不一樣的數字，若一樣會導致後面的操作不成功
[root@gary mysql]# /etc/init.d/mysqld restart //重啓MysqL
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
修改配置示例圖
2.把主上庫同步到從上
[root@gary mysql]# scp 172.16.111.100:/tmp/*.sql /tmp/
The authenticity of host '172.16.111.100 (172.16.111.100)' can't be established.
ECDSA key fingerprint is 89:19:99:8c:63:ff:d9:e6:19:0d:81:03:27:54:49:78.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '172.16.111.100' (ECDSA) to the list of known hosts.
[email protected]'s password:
Permission denied, please try again.
[email protected]'s password:
my2.sql 100% 638KB 637.7KB/s 00:00
zrlog.sql
[root@gary ~]# mysql -uroot
-bash: mysql: 未找到命令
[root@gary ~]# alias 'mysql=/usr/local/mysql/bin/mysql'
[root@gary ~]# alias 'mysqldump=/usr/local/mysql/bin/mysqldump'
[root@gary ~]# mysql -uroot
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.35 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, 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> create database aming;
Query OK, 1 row affected (0.00 sec)
mysql> create database zrlog;
Query OK, 1 row affected (0.00 sec)
mysql> create database mysql2;
Query OK, 1 row affected (0.00 sec)
mysql> quit
Bye
3.恢復數據
[root@gary mysql]# mysql -uroot zrlog < /tmp/zrlog.sql
[root@gary mysql]# mysql -uroot aming < /tmp/zrlog.sql
[root@gary mysql]# mysql -uroot mysql2 < /tmp/my2.sql 4.實現主從
[root@gary mysql]# mysql -uroot
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.6.35 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, 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;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> change master to master_host='172.16.111.100', master_user='repl', master_password='szyino-123', master_log_file='aminglinux1.000001', master_log_pos=12777;
Query OK, 0 rows affected, 2 warnings (0.02 sec)
#解釋說明：
change master這個命令是一條，打完逗號後可以按回車，直到你打分號纔算結束，其中，master_log_file和master_log_pos是在前面使用show master status命令查到的數據。
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G //查看主從是否配置成功
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.111.100
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: aminglinux1.000001
Read_Master_Log_Pos: 12777
Relay_Log_File: gary-relay-bin.000002
Relay_Log_Pos: 285
Relay_Master_Log_File: aminglinux1.000001
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: 12777
Relay_Log_Space: 457
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:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 100
Master_UUID: ccffc787-eafa-11e7-9474-000c2909e558
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)
#解釋說明：
看是否有,兩個Yes說明配置成功。
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
還需關注
Seconds_Behind_Master: 0 //爲主從延遲的時間
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
如果主從不正常了，需要看這裏的error信息。
配置成功示例圖：
5.到主上機器開啓數據庫寫操作
[root@gary-tao mysql]# mysql -uroot -pszyino-123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2407
Server version: 5.6.35-log MySQL Community Server (GPL)
Copyright (c) 2000, 2016, 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; //執行開啓數據寫操作命令
Query OK, 0 rows affected (0.00 sec)
測試主從同步
1.說明幾個配置參數
主服務器上，這兩個參數用一個就可以了。
binlog-do-db= //定義需要同步指定的庫，多個庫用英文的逗號分隔。
binlog-ignore-db= //定義不需要同步的庫。
從服務器上
replicate_do_db= //定義需要同步指定的庫，多個庫用英文的逗號分隔
replicate_ignore_db= //定義不需要同步的庫。
replicate_do_table= //定義需要同步的表
replicate_ignore_table= //定義不需要同步的表
replicate_wild_do_table= //如aming庫.%, 支持通配符%（主要使用）
replicate_wild_ignore_table=
2.測試主從同步
[root@gary-tao mysql]# mysql -uroot -pszyino-123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2407
Server version: 5.6.35-log MySQL Community Server (GPL)
Copyright (c) 2000, 2016, 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> use aming;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+-----------------+
| Tables_in_aming |
+-----------------+
| comment |
| link |
| log |
| lognav |
| plugin |
| tag |
| type |
| user |
| website |
+-----------------+
9 rows in set (0.00 sec)
//進入主上查看website錶行數
mysql> select count(*) website;
+---------+
| website |
+---------+
| 1 |
+---------+
1 row in set (0.00 sec)
mysql> truncate table website;
Query OK, 0 rows affected (0.03 sec)
//進入從上查看user錶行數
mysql> use aming;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select count(*) website;
+---------+
| website |
+---------+
| 1 |
+---------+
1 row in set (0.00 sec)
//清空主上的website表內容
mysql> truncate table website;
Query OK, 0 rows affected (0.03 sec)
//再次查看主上wedsite表雖然顯示一行，但是內容已爲空。
mysql> select count(*) website;
+---------+
| website |
+---------+
| 1 |
+---------+
1 row in set (0.00 sec)
mysql> select * from website;
Empty set (0.00 sec)
//查看從上的wedsite內容已爲空。
mysql> select count(*) from website;
+----------+
| count(*) |
+----------+
| 0 |
+----------+
1 row in set (0.00 sec)
//在主上刪除website這個表
mysql> drop table website;
Query OK, 0 rows affected (0.02 sec)
//在從上查看websitep這個表已被刪除
mysql> select * from webiste;
ERROR 1146 (42S02): Table 'aming.webiste' doesn't exist
注意：如果不小心在從上刪除了表，你再次打開查看主從配置時，發現報錯了，如下：
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.111.100
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: aminglinux1.000001
Read_Master_Log_Pos: 12997
Relay_Log_File: gary-relay-bin.000002
Relay_Log_Pos: 383
Relay_Master_Log_File: aminglinux1.000001
Slave_IO_Running: Yes
Slave_SQL_Running: No //這裏變NO了
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1051
Last_Error: Error 'Unknown table 'aming.website'' on query. Default database: 'aming'. Query: 'DROP TABLE `website` /* generated by server */'
Skip_Counter: 0
Exec_Master_Log_Pos: 12875
Relay_Log_Space: 677
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: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1051
Last_SQL_Error: Error 'Unknown table 'aming.website'' on query. Default database: 'aming'. Query: 'DROP TABLE `website` /* generated by server */'
Replicate_Ignore_Server_Ids:
Master_Server_Id: 100
Master_UUID: ccffc787-eafa-11e7-9474-000c2909e558
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State:
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp: 180123 15:28:37
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)
如果出現了這個情況只能重新做主從：
主上操作查看master:
mysql> show master status;
+--------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+--------------------+----------+--------------+------------------+-------------------+
| aminglinux1.000001 | 12997 | | | |
+--------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
從上配置change master重做主從（爲什麼可以直接做主從，因爲數據還是一致的，沒有做其它的操作）
mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)
//除了最後面數字需要更改，其它參數都一樣。
mysql> change master to master_host='172.16.111.100', master_user='repl', master_password='szyino-123', master_log_file='aminglinux1.000001', master_log_pos=12997;
Query OK, 0 rows affected, 2 warnings (0.02 sec)
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: 172.16.111.100
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: aminglinux1.000001
Read_Master_Log_Pos: 12997
Relay_Log_File: gary-relay-bin.000002
Relay_Log_Pos: 285
Relay_Master_Log_File: aminglinux1.000001
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: 12997
Relay_Log_Space: 457
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:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 100
Master_UUID: ccffc787-eafa-11e7-9474-000c2909e558
Master_Info_File: /data/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)