Replication, 复制是高可用的基础, MHA,mycat 等中间件的底层都依赖复制原理
master 主实例 slave 从实例
分类: 默认的异步复制, 5.5 版本后的半同步复制, 5.6 版本新增的 GTID 复制, 5.7 版本的多源复制, 基于组提交的并行复制和增强半同步复制
复制方法: 1. 传统方法: 基于 binlog 日志复制 2.GTID: 基于事物复制
binlog 可以有不同的格式: 基于语句, 基于行数据, 混合(行数据复制是默认)
下面搭建下常规的异步复制
必要条件: server_id 在主从之间不同; 主库开启 binlog, 建议从库也开启方便架构扩展
首先编辑 my.cnf 开启 binlog 并设置 server_id
- MySQL> show variables like '%log_bin%';
- +---------------------------------+---------------------------------------+
- | Variable_name | Value |
- +---------------------------------+---------------------------------------+
- | log_bin | ON |
- | log_bin_basename | /usr/local/MySQL/data/MySQL-bin |
- | log_bin_index | /usr/local/MySQL/data/MySQL-bin.index |
- | log_bin_trust_function_creators | OFF |
- | log_bin_use_v1_row_events | OFF |
- | sql_log_bin | ON |
- +---------------------------------+---------------------------------------+
- 6 rows in set (0.00 sec)
- MySQL> ^DBye
- [root@localhost ~]$ cat /etc/my.cnf
- [mysqld]
- datadir=/usr/local/MySQL/data
- log_bin=MySQL-bin
- server_id=1
- [root@localhost ~]$
然后创建主从复制的用户, 之前实验已经创建了 scott 用户, 就用这个了, 再赋权(因为会密码会明文保存在 slave 的 master.info 所以实际上应该单独建立个只有复制权限的用户)
- MySQL> grant replication slave on *.* to 'scott'@'%';
- Query OK, 0 rows affected (0.00 sec)
表加锁停止修改
- MySQL> flush tables with read lock;
- Query OK, 0 rows affected (0.01 sec)
- MySQL> show master status;
- +------------------+----------+--------------+------------------+-------------------+
- | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
- +------------------+----------+--------------+------------------+-------------------+
- | MySQL-bin.000003 | 556 | | | |
- +------------------+----------+--------------+------------------+-------------------+
- 1 row in set (0.00 sec)
- MySQL> drop table tmp;
- ERROR 122
然后将主库全量备份一个传给备库, 可以直接 data 目录打包过去 (innodb 不推荐) 或者直接 mysqldump
- [root@localhost ~]$ mysqldump --all-databases -uroot -pmysql --master-data> dbdump.db
- mysqldump: [Warning] Using a password on the command line interface can be insecure.
- [root@localhost ~]$ ls
- dbdump.db
- [root@localhost ~]$ scp dbdump.db 192.0.1.11:~
- The authenticity of host '192.0.1.11 (192.0.1.11)' can't be established.
- ECDSA key fingerprint is SHA256:pmk8Q9EnT+TugRZ5rb2bc0GP20ZV3LkeuXP/Jrw5tbs.
- ECDSA key fingerprint is MD5:13:d1:4a:14:3a:4d:fd:33:56:15:f9:1f:2f:44:87:2c.
- Are you sure you want to continue connecting (yes/no)? yes
- Warning: Permanently added '192.0.1.11' (ECDSA) to the list of known hosts.
- root@192.0.1.11's password:
- dbdump.db
然后在备库中应用
MySQL> source dbdump.db
从库中配置主库信息
- MySQL> change master to
- -> master_host='192.0.1.10',
- -> master_user='scott',
- -> master_password='tiger',
- -> master_port=3306,
- -> master_log_file='mysql-bin.000003',
- -> master_log_pos=556;
- Query OK, 0 rows affected, 2 warnings (0.01 sec)
- MySQL>
开启同步
- 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: 192.0.1.10
- Master_User: scott
- Master_Port: 3306
- Connect_Retry: 60
- Master_Log_File: MySQL-bin.000003
- Read_Master_Log_Pos: 556
- Relay_Log_File: localhost-relay-bin.000002
- Relay_Log_Pos: 320
- Relay_Master_Log_File: MySQL-bin.000003
- 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: 556
- Relay_Log_Space: 531
- 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: 531fa6d1-627f-11e9-8dc7-000c297887a1
- Master_Info_File: /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)
- ERROR:
- No query specified
- MySQL>
释放主库锁定
- MySQL> unlock tables;
- Query OK, 0 rows affected (0.00 sec)
好了验证下, 主库中插入记录, 从库立刻就有了
来源: http://www.linuxidc.com/Linux/2019-08/160087.htm