Introduction to the master-slave architecture
mysql The built-in replica mechanism allows you to switch from a mysql database （ It's called the master or source library ） Copy one or more mysql database （ It's called a slave or replica Library ）. The replication mechanism is asynchronous by default , No persistent connection is required to receive updates from the source library . The scope of replica mechanism can be all databases , Selected database or selected table .
MySQL 8.0 Supports two different replication methods ：
1） Based on binary log from source library （binary log） Copy event implementation , It also requires that the log file and the location in the log file be synchronized between the source library and the replica library , Asynchronous implementation , It's not transactional .
2） Based on the global transaction identifier (GTIDs) Realization , It's transactional , So there's no need to deal with log files and their locations , This greatly simplifies many common replication tasks . As long as all transactions committed on the source database also apply to the replica database , Use GTIDs Replication ensures consistency between the source and the replica .
Advantages of master-slave architecture
- Can achieve read-write separation architecture , Write to the main database , Read from the library , You can load the replica library to improve overall performance .
- It can protect data security , Because the replica can pause the replication process , So you can run the backup service on the replica , Without damaging the corresponding source data .
- Data backup can be realized , Disaster recovery
be based on binary log Master slave architecture practice
Master database settings
The first is in MySQL Add a user who can copy master-slave permissions . stay mysql Execute the following commands in the interactive environment
# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 14
Server version: 8.0.13 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'@'10.20.131.38' identified by '[email protected]#';
Query OK, 0 rows affected (0.07 sec)
mysql> grant replication slave on *.* to 'repl'@'10.20.131.38';
Query OK, 0 rows affected (0.05 sec)
mysql> show master status;
+---------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+----------+--------------+------------------+-------------------+
| binlog.000001 | 2324 | | | |
+---------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql>
command **show master status ** Get the name and location of the current archive log , When setting master-slave replication from the server, you need to start from this location .
From library settings
# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 8.0.13 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> change master to
-> master_host='10.20.131.37',
-> master_port=3306,
-> master_user='repl',
-> master_password='[email protected]#',
-> master_log_file='binlog.000001',
-> master_log_pos=2324;
Query OK, 0 rows affected, 2 warnings (0.07 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.20.131.37
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000001
Read_Master_Log_Pos: 2324
Relay_Log_File: h10p20p131p38-relay-bin.000002
Relay_Log_Pos: 319
Relay_Master_Log_File: binlog.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: 2324
Relay_Log_Space: 535
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: 37
Master_UUID: 109ae7ea-1d7c-11eb-980d-48f97cff3ddf
Master_Info_File: mysql.slave_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:
Master_public_key_path:
Get_master_public_key: 0
1 row in set (0.00 sec)
ERROR:
No query specified
Slave_IO_State The value of is Waiting for master to send event , It means that you are ready to accept the archive log sent by the main database for processing .
Test master-slave replication
The name of the main database is test Of database, as follows ：
mysql> create database test default character set utf8;
Query OK, 1 row affected, 1 warning (0.03 sec)
Confirm whether the backup has been synchronized from the database , as follows ：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
+--------------------+
5 rows in set (0.00 sec)
mysql>
According to the above output , You can confirm that master-slave replication is in effect .