mysql主從配置實現一主一從讀寫分離
阿新 • • 發佈：2018-09-07
配置文件 狀態 main ado man datadir lai community more 主從介紹
定義
- Mysql主從又叫Replication、AB復制。簡單講就是A與B兩臺機器做主從後，在A上寫數據，另外一臺B也會跟著寫數據，實現數據實時同步
- mysql主從是基於binlog，主上需開啟binlog才能進行主從
-
主從過程大概有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裏面的sql語句落地
主從的應用場景：
數據的高可用。（主：作為讀寫數據，從：實時同步，當主宕機時，從 也可以及時提供服務）
數據的負載均衡。（客戶從 從 這臺機器上讀取數據（但是不
主從作用
- 實時災備，用於故障切換
- 讀寫分離，提供查詢服務
- 備份，避免影響業務
主從形式
- 一主一從
- 主主復制
- 一主多從---擴展系統讀取的性能，因為讀是在從庫讀取的
- 多主一從---5.7版本開始支持
- 聯級復制
主從復制原理
主從復制步驟
- 主庫將所有的寫操作記錄在binlog日誌中，並生成log dump線程，將binlog日誌傳給從庫的I/O線程
-
從庫生成兩個線程，一個是I/O線程，另一個是SQL線程
- I/O線程去請求主庫的binlog日誌，並將binlog日誌中的文件寫入relay log（中繼日誌）中
- SQL線程會讀取relay loy中的內容，並解析成具體的操作，來實現主從的操作一致，達到最終數據一致的目的
主從復制配置
主從復制配置步驟：
- 確保從數據庫與主數據庫裏的數據一致
- 在主數據庫裏創建一個同步賬戶授權給從數據庫使用
- 配合主數據庫（修改配置文件）
4.配置從數據庫（修改配置文件）需求
搭建兩臺
MYSQL服務器，一臺作為主服務器，一臺作為從服務器，主服務器進行寫操作，從服務器進行讀操作環境說明
| 數據庫角色 | IP | 應用與系統 | 有無數據 |
|---|---|---|---|
| 主數據庫 | 192.168.24.18 | centos7 mysql-5.7 | 有 |
| 從數據庫 | 192.168.24.129 | centos7 mysql-5.7 | 無 |
在兩臺服務器上都按裝mysql
具體配置查看《mysql進階簡單解析》
mysql主從配置
確保從數據庫與主數據庫的數據一樣
先在主數據庫創建所需要同步的庫和表
[root@linfan ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.22 MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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 doudou;
Query OK, 1 row affected (0.03 sec)
mysql> create database job;
Query OK, 1 row affected (0.00 sec)
mysql> create database mary;
Query OK, 1 row affected (0.00 sec)
mysql> use doudou;
Database changed
mysql> create table tom (id int not null,name varchar(100) not null,age tinyint);
Query OK, 0 rows affected (0.22 sec)
mysql> insert tom(id,name,age) values(1,"lisi",6),(2,"waangwu",5),(3,"zhaotie",9);
Query OK, 3 rows affected (0.07 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from tom;
+----+---------+------+
| id | name | age |
+----+---------+------+
| 1 | lisi | 6 |
| 2 | waangwu | 5 |
| 3 | zhaotie | 9 |
+----+---------+------+
3 rows in set (0.01 sec)
mysql> 備份主庫
備份主庫時需要另開一個終端，給數據庫上讀鎖，避免在備份期間有其他人在寫入導致數據同步的不一致
[root@linfan ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.22 MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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 (0.17 sec)
mysql> //此鎖表的終端必須在備份完成以後才能退出（退出鎖表失效） 備份主庫並將備份文件傳送到從庫
[root@linfan ~]# mysqldump -uroot -plinfan123 --all-databases >/opt/all-20180907.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@linfan ~]# ls /opt/
all-20180907.sql data
[root@linfan ~]# scp /opt/all-20180907.sql [email protected]:/opt/
The authenticity of host ‘192.168.24.130 (192.168.24.130)‘ can‘t be established.
ECDSA key fingerprint is SHA256:w+sgREnQRuhBiqS0qL9wlAImCSmvSQ6KnNqW6N3znJ0.
ECDSA key fingerprint is MD5:f0:fd:ea:c7:97:83:f0:b0:03:84:d2:a6:0a:23:12:e0.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.24.130‘ (ECDSA) to the list of known hosts.
[email protected]‘s password:
all-20180907.sql 100%解除主庫的鎖表狀態，直接退出交互式界面即可
mysql> quit
Bye在從庫上恢復主庫的備份並查看是否與主庫的數據保持一致
[root@linfan ~]# mysql -uroot -plinfan123 < /opt/all-20180907.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@linfan ~]# mysql -uroot -plinfan123
mysql: [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 4
Server version: 5.7.22 MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| doudou |
| job |
| mary |
| mysql |
| performance_schema |
| sys |
+--------------------+
7 rows in set (0.01 sec)
mysql> use doudou
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 * from tom;
+----+---------+------+
| id | name | age |
+----+---------+------+
| 1 | lisi | 6 |
| 2 | waangwu | 5 |
| 3 | zhaotie | 9 |
+----+---------+------+
3 rows in set (0.00 sec)
在主數據庫創建一個同步賬戶授權給從數據使用
[root@linfan ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.22 MySQL Community Server (GPL)
Copyright (c) 2000, 2018, 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 user ‘repl‘@‘192.168.24.130‘ identified by ‘123456‘;
Query OK, 0 rows affected (0.04 sec)
mysql> grant replication slave on *.* to ‘repl‘@‘192.168.24.130‘;
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
配置主數據庫
編輯配置文件
[root@linfan ~]# vim /etc/my.cnf
[root@linfan ~]# cat /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
//添加以下內容
log-bin=mysql-bin //啟用binlog日誌
server-id=1 //主數據庫服務器唯一標識符 主的必須必從大
log-error=/opt/data/mysql.log重啟mysql服務
[root@linfan ~]# service mysqld restart
Shutting down MySQL... SUCCESS!
Starting MySQL.Logging to ‘/opt/data/mysql.log‘.
.......... SUCCESS!
[root@linfan ~]# ss -natl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 80 :::3306 查看主庫的狀態（裏面的數據要記住，待會會用到）
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 154 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)配置從數據庫
編輯配置文件
[root@linfan ~]# cat /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
//添加以下內容：
server-id=2 //設置從庫的唯一標識符 從的必須比主小
relay-log=mysql-relay-bin //啟用中繼日誌relay log
error-log=/opt/data/mysql.log重啟從庫的mysql服務
[root@linfan ~]# service mysqld restart
Shutting down MySQL... SUCCESS!
Starting MySQL.Logging to ‘/opt/data/mysql.log‘.
.......... SUCCESS!
[root@linfan ~]# ss -natl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 80 :::3306 配置並啟動主從復制
mysql> change master to
-> master_host=‘192.168.24.128‘,
-> master_user=‘repl‘,
-> master_password=‘123456‘,
-> master_log_file=‘mysql-bin.000001‘,
-> master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.02 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec) 查看從服務器狀態
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.24.128
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 154
Relay_Log_File: linfan-relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes //此處必須為yes
Slave_SQL_Running: Yes
//此處必須為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: 154
Relay_Log_Space: 528
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: 1
Master_UUID: 3396fe35-b1e1-11e8-81bb-000c292340f6
Master_Info_File: /opt/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
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
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec) 測試驗證
在主服務器的doudou庫的tom表插入數據:
mysql> use doudou;
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 * from tom;
+----+---------+------+
| id | name | age |
+----+---------+------+
| 1 | lisi | 6 |
| 2 | waangwu | 5 |
| 3 | zhaotie | 9 |
+----+---------+------+
3 rows in set (0.00 sec)
mysql> insert tom(id,name,age) value (4,"mary",18);
Query OK, 1 row affected (0.10 sec)
mysql> select * from tom;
+----+---------+------+
| id | name | age |
+----+---------+------+
| 1 | lisi | 6 |
| 2 | waangwu | 5 |
| 3 | zhaotie | 9 |
| 4 | mary | 18 |
+----+---------+------+
4 rows in set (0.00 sec)在從數據庫查看是否數據同步
mysql> use doudou;
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 * from tom;
+----+---------+------+
| id | name | age |
+----+---------+------+
| 1 | lisi | 6 |
| 2 | waangwu | 5 |
| 3 | zhaotie | 9 |
| 4 | mary | 18 |
+----+---------+------+
4 rows in set (0.00 sec)
mysql主從配置實現一主一從讀寫分離