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
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