MySQL主从复制原理及其配置过程

一、MySQL复制原理。

二、MySQL复制配置。

一、MySQL复制原理
1.MySQL复制原理图



复制原理：

Slave启动IO Thread和SQL Thread
Master启动DumpThread

1.Slave通过IO Thread向Master的Dump Thread发送请求，Master的Dump Thread请求本地的binlog。
2.Master读取本地的binlog，并将读取内容发送给Slave的IO Thread线程。
3.Slave的IO Thread将收到的内容，写入到本地的relaylog中。
4.Slave的SQL Thread读取本地的relaylog文件内容。
5.Slave的SQL Thread将读取的内容写入到本地数据库。
二、MySQL复制配置
1.MySQL复制图



2.配置Master
2.1.修改Master配置文件

vim /etc/my.cnf
[mysqld]
#开启二进制日志文件
log-bin = mysql-bin
#配置唯一server id
server-id = 1
#事务安全
sync_master_info = 1
sync_binlog = 1
innodb_support_xa = ON

2.2.Master配置文件全文

[client]
port  = 3306
socket = /tmp/mysql.sock

[mysqld]
port = 3306
socket = /tmp/mysql.sock
skip-external-locking
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
thread_concurrency = 8

log-bin=mysql-bin
binlog_format=mixed

server-id = 1
sync_master_info = 1
sync_binlog = 1
innodb_support_xa = ON
datadir = /data/mysql/3306/data
innodb_data_home_dir = /data/mysql/3306/data
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /data/mysql/3306/data
innodb_buffer_pool_size = 256M
innodb_additional_mem_pool_size = 20M
innodb_log_file_size = 64M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 2
innodb_lock_wait_timeout = 50
innodb_file_per_table = ON
skip_name_resolve = ON

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

2.3.创建复制权限的用户

MariaDB [(none)]> grant replication slave,replication client on *.* to 'repl'@'192.168.1.5' identified by 'slavepass';
Query OK, 0 rows affected (0.39 sec)

MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.06 sec)

3.配置Slave
3.1.修改Slave配置文件

vim /etc/my.cnf
[mysqld]
#设置唯一ID
server-id = 3
#启用relay log
relay_log= relay-log
relay_log_index=relay-log.index
#事务安全
skip_slave_start = ON
sync_relay_log = 1
sync_relay_log_info = 1

3.3.slave配置文件全文

[client]
port            = 3306
socket          = /tmp/mysql.sock

[mysqld]
port            = 3306
socket          = /tmp/mysql.sock
skip-external-locking
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
read_rnd_buffer_size = 4M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size= 16M
thread_concurrency = 8

server-id = 3
relay_log= relay-log
relay_log_index=relay-log.index
skip_slave_start = ON
sync_relay_log = 1
sync_relay_log_info = 1

innodb_data_home_dir = /data/mysql/3306/data
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /data/mysql/3306/data
innodb_buffer_pool_size = 256M
innodb_additional_mem_pool_size = 20M
innodb_log_file_size = 64M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 2
innodb_lock_wait_timeout = 50
innodb_file_per_table = ON
skip_name_resolve = ON

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

4.开始复制
4.1.在Master上查看binlog Pos点

MariaDB [(none)]> show master status\G
*************************** 1. row ***************************
File: mysql-bin.000008
Position: 652
Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)

4.2.在slave上执行同步操作

MariaDB [(none)]> change master to master_host='192.168.1.4',master_user='repl',master_password='slavepass',master_log_file='mysql-bin.000008',master_log_pos=652;
Query OK, 0 rows affected (0.93 sec)

4.3.在slave上启动slave

MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.02 sec)

4.3.在slave上查看slave状态

MariaDB [(none)]> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.4
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000008
Read_Master_Log_Pos: 652
Relay_Log_File: relay-log.000002
Relay_Log_Pos: 537
Relay_Master_Log_File: mysql-bin.000008
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: 652
Relay_Log_Space: 829
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_SSL_Crl:
Master_SSL_Crlpath:
Using_Gtid: No
Gtid_IO_Pos:
Replicate_Do_Domain_Ids:
Replicate_Ignore_Domain_Ids:
Parallel_Mode: conservative
1 row in set (0.00 sec)

5.测试同步
5.1.在master创建数据

MariaDB [(none)]> create database ckldb;
Query OK, 1 row affected (0.37 sec)

MariaDB [(none)]> use ckldb;
Database changed
MariaDB [ckldb]> create table jone(id int,name varchar(30));
Query OK, 0 rows affected (0.29 sec)

MariaDB [ckldb]> insert into jone values(1,'wukaka');
Query OK, 1 row affected (0.49 sec)

MariaDB [ckldb]> delete from jone;
Query OK, 1 row affected (0.09 sec)

MariaDB [ckldb]> insert into jone values(1,'wukaka'),(2,'side');
Query OK, 2 rows affected (0.06 sec)
Records: 2  Duplicates: 0  Warnings: 0

MariaDB [ckldb]> select * from jone;
+------+--------+
| id   | name   |
+------+--------+
|    1 | wukaka |
|    2 | side   |
+------+--------+
2 rows in set (0.00 sec)

5.2.在slave上查看

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| ckldb              |
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
5 rows in set (0.34 sec)

MariaDB [(none)]> use ckldb;
Database changed
MariaDB [ckldb]> show tables;
+-----------------+
| Tables_in_ckldb |
+-----------------+
| jone            |
+-----------------+
1 row in set (0.00 sec)

MariaDB [ckldb]> select * from jone;
+------+--------+
| id   | name   |
+------+--------+
|    1 | wukaka |
|    2 | side   |
+------+--------+
2 rows in set (0.00 sec)

注意，如果主库已经运行很久，同步之前最好，备份主库，记录binlog Pos点。将备份导入到slave库
，然后从binlog Pos开始恢复。