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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
：
正文完
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