MySQL主從同步

主從同步概述

MySQL主從同步

• 主從同步介紹

• 實現數據自動同步的服務結構
• 主服務器：接受客戶端訪問連接
• 從服務器：自動同步主服務器的數據

主從同步的工作原理

主庫有1個線程叫dump線程，從庫有2個線程（io+sql）,當主庫有數據發生改變的時候，那么主庫會通過自己的dump線程去給從庫發個信號，然后從庫再去請求主庫的binlog日志文件并保存在本機的中繼日志文件里面，然后sql線程執行中繼日志文件里面的SQL信息，完成同步。

• Master
• 啟用binlog日志
• Slave
• Slave_IO：復制master主機binlog日志文件里的SQL命令到本機的relay-log文件里
• Slave_SQL：執行本機的relay-log文件里的SQL語句，實現與Master數據一致

構建主從同步

構建思路

• 配置主服務器
• 啟用binlog日志、授權用戶、查看binlog日志
• 配置從服務器
• 設置server_id
• 確保與主服務器數據一致
• 指定主庫信息
• 啟動slave程序
• 查看狀態信息

拓撲結構圖

構建主服務器

- 修改主配置文件 啟動binlog日志，并重啟服務 [root@host51 ~]# vim /etc/my.cnf 4 [mysqld] 5 server_id=51 #指定服務器id 6 log_bin=master51 #啟用binlog日志 [root@host51 ~]# systemctl restart mysqld - 授權用戶 用戶權限replication slave 用戶名自定義 客戶端地址允許從服務器連接 密碼自定義，但要符合密碼策略 [root@host51 ~]# mysql -uroot -p123456 mysql> grant replication slave on *.* to repluser@"%" identified by "123qqq...A"; mysql> select user ,host from mysql.user where user="repluser"; +----------+------+ | user | host | +----------+------+ | repluser | % | +----------+------+ 1 row in set (0.00 sec) mysql> show master status; #查看日志信息 +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master51.000001 | 441 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)

配置從服務器

- 修改主配置文件my.cnf server_id不允許與主服務器server_id相同 [root@host52 ~]# vim /etc/my.cnf4 [mysqld]5 server_id=52 #指定服務器id [root@host52 ~]# systemctl restart mysqld - 確保與主服務器數據一致 1. 在主服務器上備份數據，將備份文件拷貝給從服務器 2. 從服務器使用備份文件恢復數據 3. 在從服務器上查看備份文件記錄的binlog日志 [root@host51 ~]# mysqldump -uroot -p123456 --master-data db1 > /allbak.sql #主庫備份數據，--master-data記錄當前備份數據對應的日志信息 [root@host51 ~]# ls /allbak.sql /allbak.sql [root@host51 ~]# scp /allbak.sql root@192.168.4.52:/root [root@host52 ~]# ls allbak.sql [root@host52 ~]# mysql -uroot -p123456 db1 < /root/allbak.sql #一定要先在從服務器上創建與主服務器同名的數據庫 [root@host52 ~]# grep "master" /root/allbak.sql CHANGE MASTER TO MASTER_LOG_FILE='master51.000001', MASTER_LOG_POS=441; #查看binlog日志以及偏移量 - 指定主服務器信息 [root@host52 ~]# mysql -uroot -p123456 mysql> show slave status; Empty set (0.00 sec)mysql> change master to-> master_host="192.168.4.51" , #主服務器IP地址-> master_user="repluser" , #主服務器授權用戶-> master_password="123qqq...A" , #授權密碼-> master_log_file="master51.000001" , #主服務器binlog日志-> master_log_pos=441 ; #日志偏移量 Query OK, 0 rows affected, 2 warnings (0.06 sec) mysql> start slave; #啟動slave進程 Query OK, 0 rows affected (0.00 sec)1. Master信息會自動保存到/var/lib/mysql/master.info文件 2. 若更改主服務器信息時，應先執行stop slave;修改后在執行start slave;- 查看Slave狀態 確認IO線程，SQL線程都是Yes狀態 mysql> show slave status \G *************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.4.51 #主服務器IP地址Master_User: repluserMaster_Port: 3306Connect_Retry: 60Master_Log_File: master51.000001Read_Master_Log_Pos: 441Relay_Log_File: host52-relay-bin.000004Relay_Log_Pos: 319Relay_Master_Log_File: master51.000001Slave_IO_Running: Yes #IO線程已經運行Slave_SQL_Running: Yes #SQL線程已經運行Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 441Relay_Log_Space: 692Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 51Master_UUID: 6d7b632c-4e3f-11ea-8a8d-000c29875030Master_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec) #要確保IO以及SQL都是yes狀態，才可以與主服務器保持數據一致 # Last_IO_Error：slave_IO_Running的報錯信息 # Last_SQL_Error：slave_SQL_Running的報錯信息如果報錯檢查Last_IO_Error以及Last_SQL_Error，然后根據錯誤進行修改，stop slave ，再次重新寫change master，然后重新start slave，查看信息狀態 change master to master_user="用戶名" change master to master_host="主服務器地址" change master to master_password="主服務器設置的密碼" change master to master_log_file="主服務器的binlog日志名" change master to master_log_pos=主服務器的偏移量 ; （ps：當如果報錯號碼為2003，此時檢查防火墻與selinux的狀態，確保防火墻關閉，selinux為permissive狀態）

將從服務器恢復成獨立的數據庫

• 存放在數據庫目錄下的相關文件
• 將以下文件全部刪除，重啟服務，即可恢復成獨立的數據庫

文件名說明

master.info	主庫信息
relay-log.info	中繼日志信息
主機名-relay-bin.xxxxxx	中繼日志
主機名-relay-bin.index	索引文件

[root@host52 ~]# cd /var/lib/mysql [root@host52 mysql]# ls auto.cnf ibdata1 mysql sys host52-relay-bin.000003 ib_logfile0 mysql.sock xtrabackup_binlog_pos_innodb host52-relay-bin.000004 ib_logfile1 mysql.sock.lock xtrabackup_info host52-relay-bin.index ibtmp1 performance_schema ib_buffer_pool master.info relay-log.info [root@host52 mysql]# cat master.info #此處是主庫信息 25 master51.000001 441 192.168.4.51 repluser 123qqq...A 3306 60 00 30.0000 6d7b632c-4e3f-11ea-8a8d-000c29875030 864000[root@host52 mysql]#rm -rf master.info [root@host52 mysql]#rm -rf relay-log.info [root@host52 mysql]#rm -rf host52-replay-bin.* [root@host52 mysql]#systemctl restart mysqld [root@host52 ~]# mysql -uroot -p123456 mysql>show slave status; mysql> change master to-> master_host="192.168.4.51" ,-> master_user="repluser" ,-> master_password="123qqq...A" ,-> master_log_file="master51.000001" ,-> master_log_pos=441 ; Query OK, 0 rows affected, 2 warnings (0.06 sec) mysql>start slave; mysql>show slave status; 測試： 在主服務器上新寫入數據，在從服務器上面查看 [root@host51 ~]# mysql -uroot -p123456 mysql> create database db5; Query OK, 1 row affected (0.00 sec)mysql> create table db5.user(name char(12)); Query OK, 0 rows affected (0.01 sec)mysql> insert into db5.user values("haha"); Query OK, 1 row affected (0.02 sec)mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master51.000001 | 1024 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)在host52上面查看 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | db1 | | db5 | | mysql | | performance_schema | | sys | +--------------------+ 6 rows in set (0.05 sec)mysql> select * from db5.user; +------+ | name | +------+ | haha | +------+ 1 row in set (0.00 sec)

構建主從同步結構模式

結構類型

• 基本應用

• 單向復制：一主 <-- 一從

• 擴展應用

• 一主多從：從 <-- 主 --> 從
• 鏈式復制：主 <-- 從 <-- 從
• 互為主從：主 < – > 主

配置一主多從結構

• 拓撲圖如下
  

- 配置從服務器53 1. 修改配置文件 2. 確保與主服務器數據一致 3. 指定主庫信息 4. 啟動slave進程[root@host53 ~]# vim /etc/my.cnf4 [mysqld]5 server_id=53[root@host51 ~]# mysqldump -uroot -p123456 db5 > /root/db5.sql [root@host51 ~]# scp -r /root/db5.sql root@192.168.4.53:/root [root@host51 ~]# mysql -uroot -p123456 mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master51.000001 | 1024 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec) [root@host53 ~]# mysql -uroot -p123456 mysql> create database db5; [root@host53 ~]# mysql -uroot -p123456 db5 < /root/db5.sql[root@host53 ~]# mysql -uroot -p123456 mysql> change master to -> master_host="192.168.4.51" ,-> master_user="repluser" ,-> master_password="123qqq...A" ,-> master_log_file="master51.000001" ,-> master_log_pos=1024 ; Query OK, 0 rows affected, 2 warnings (0.07 sec) mysql> show slave status \G *************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.4.51Master_User: repluserMaster_Port: 3306Connect_Retry: 60Master_Log_File: master51.000001Read_Master_Log_Pos: 1024Relay_Log_File: host53-relay-bin.000003Relay_Log_Pos: 319Relay_Master_Log_File: master51.000001Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 1024Relay_Log_Space: 527Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 51Master_UUID: 6d7b632c-4e3f-11ea-8a8d-000c29875030Master_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec)UUID問題：如果報錯UUID沖突，可能是由于之前做過的實驗將所有數據備份過來導致uid也是相同的，解決辦法如下：進到/var/lib/mysql數據庫目錄，修改/var/lib/mysql/auto.cnf, 改一個新的值，但與原來的長度一定要相同，重啟數據庫服務即可，或者也可以進到數據庫select uid();獲取新的uid復制到/var/lib/mysql/auto.cnf中[root@host51 ~]# mysql -uroot -p123456 mysql> select * from db5.user; +---------+ | name | +---------+ | haha | | heihei | | lalalla | | jkfjf | | uuuuu | | sss | | ggg | +---------+ 7 rows in set (0.00 sec)[root@host52 ~]# mysql -uroot -p123456 mysql> select * from db5.user; +---------+ | name | +---------+ | haha | | heihei | | lalalla | | jkfjf | | uuuuu | | sss | | ggg | +---------+ 7 rows in set (0.01 sec)[root@host53 ~]# mysql -uroot -p123456 mysql> select * from db5.user; +---------+ | name | +---------+ | haha | | heihei | | lalalla | | jkfjf | | uuuuu | | sss | | ggg | +---------+ 7 rows in set (0.00 sec)[root@host53 mysql]# ls auto.cnf host53-relay-bin.000003 master.info relay-log.info ca-key.pem host53-relay-bin.index mysql server-cert.pem ca.pem ib_buffer_pool mysql.sock server-key.pem client-cert.pem ibdata1 mysql.sock.lock sys client-key.pem ib_logfile0 performance_schema db5 ib_logfile1 private_key.pem host53-relay-bin.000002 ibtmp1 public_key.pem [root@host53 ~]# cat /var/lib/mysql/master.info 25 master51.000001 2547 192.168.4.51 repluser 123qqq...A 3306 60 00 30.0000 6d7b632c-4e3f-11ea-8a8d-000c29875030 864000

配置主從從模式

• 拓撲圖如下
  

為了在啟用binlog日志以及通不值錢保持主、從庫的一致性，主從同步未配置之前，要保證從庫上要有主庫上的數據，禁用selinux，關閉防火墻服務，保證物理連接正常。 - 配置主服務器 1.將53主機恢復成獨立的數據庫 2. 啟用binlog日志 3. 重啟數據庫服務 4. 用戶授權 [root@host53 ~]# mysql -uroot -p123456 -e "show slave status \G" | grep 192.168.4.51 #首先查看host53當前是否為其他主機的從服務器，顯示當前為51主機的從服務器 mysql: [Warning] Using a password on the command line interface can be insecure.Master_Host: 192.168.4.51Last_IO_Error: error connecting to master 'repluser@192.168.4.51:3306' - retry-time: 60 retries: 14 [root@host53 ~]# systemctl stop mysqld #關閉服務 cd [root@host53 ~]# cd /var/lib/mysql [root@host53 mysql]# ls auto.cnf db5 ib_logfile0 private_key.pem sys ca-key.pem host53-relay-bin.000004 ib_logfile1 public_key.pem ca.pem host53-relay-bin.index master.info relay-log.info client-cert.pem ib_buffer_pool mysql server-cert.pem client-key.pem ibdata1 performance_schema server-key.pem [root@host53 mysql]# rm -rf master.info #刪除主庫的信息 [root@host53 mysql]# rm -rf relay-log.info #刪除中繼日志信息 [root@host53 mysql]# rm -rf host53-relay-bin.* #刪除所有 [root@host53 mysql]# vim /etc/my.cnf 5 #server_id=53 [root@host53 mysql]# systemctl restart mysqld [root@host53 mysql]# mysql -uroot -p123456 mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | db5 | | mysql | | performance_schema | | sys | +--------------------+ 5 rows in set (0.10 sec)mysql> drop database db5; Query OK, 1 row affected (0.12 sec)mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ 4 rows in set (0.00 sec)mysql> show master status; Empty set (0.00 sec)mysql> show slave status; Empty set (0.00 sec)[root@host53 mysql]# vim /etc/my.cnf [mysqld] server_id=53 log_bin=host53 [root@host53 mysql]# systemctl restart mysqld [root@host53 mysql]# mysql -uroot -p123456 用戶授權 mysql> grant replication slave on *.* to tian@"%" identified by "123qqq...A"; Query OK, 0 rows affected, 1 warning (0.01 sec)查看日志信息 mysql> show master status; +---------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +---------------+----------+--------------+------------------+-------------------+ | host53.000001 | 441 | | | | +---------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)- 配置服務器54（既做主服務器又做從服務器） 級聯復制：指在主服務器寫的數據，會同步到從服務器的從服務器中 1. 修改配置文件 2. 用戶授權 3. 指定主庫信息 4. 啟動slave進程 [root@host54 ~]# vim /etc/my.cnf [mysqld] log_bin=host54 server_id=54 log_slave_updates #允許級聯復制[root@host54 ~]# systemctl restart mysqld [root@host54 ~]# mysql -uroot -p123456 mysql> grant replication slave on *.* to tian@"%" identified by "123qqq...A"; Query OK, 0 rows affected, 1 warning (0.01 sec)mysql> show master status; +---------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +---------------+----------+--------------+------------------+-------------------+ | host54.000003 | 437 | | | | +---------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)mysql> change master to-> master_host="192.168.4.53",-> master_user="tian",-> master_password="123qqq...A",-> master_log_file="host53.000001",-> master_log_pos=437; Query OK, 0 rows affected, 2 warnings (0.08 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 eventMaster_Host: 192.168.4.53Master_User: tianMaster_Port: 3306Connect_Retry: 60Master_Log_File: host53.000001Read_Master_Log_Pos: 437Relay_Log_File: host54-relay-bin.000002Relay_Log_Pos: 317Relay_Master_Log_File: host53.000001Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 437Relay_Log_Space: 525Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 53Master_UUID: 5240ae91-533a-11ea-a67b-000c296c0929Master_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec)*****************************************************************- 配置從服務器55 1. 修改配置文件 2. 指定主庫信息 3. 啟動slave進程 [root@host55 ~]# vim /etc/my.cnf 5 server_id=55 [root@host55 ~]# systemctl restart mysqld [root@host55 ~]# mysql -uroot -p123qqq...A mysql> show master status; Empty set (0.00 sec)mysql> change master to-> master_host="192.168.4.54",-> master_user="tian",-> master_password="123qqq...A",-> master_log_file="host54.000003",-> master_log_pos=437; Query OK, 0 rows affected, 2 warnings (0.08 sec)mysql> start slave; Query OK, 0 rows affected (0.00 sec)mysql> show slave status\G *************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.4.54Master_User: tianMaster_Port: 3306Connect_Retry: 60Master_Log_File: host54.000003Read_Master_Log_Pos: 437Relay_Log_File: host55-relay-bin.000002Relay_Log_Pos: 317Relay_Master_Log_File: host54.000003Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 437Relay_Log_Space: 525Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 54Master_UUID: 8b4a89b4-531c-11ea-883c-000c290db2a4Master_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec)客戶端測試，在主庫上授權訪問數據的連接用戶，客戶端連接主庫執行權限匹配的SQL操作，授權用戶連接第一臺從庫，可以看到主庫的數據，授權用戶連接第二臺從庫，可以看到主庫的數據在host53上授權用戶登錄 mysql> grant all on gamedb.* to adminuser@"192.168.4.50" identified by "123qqq...A"; Query OK, 0 rows affected, 1 warning (0.11 sec)mysql> show master status; +---------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +---------------+----------+--------------+------------------+-------------------+ | host53.000001 | 751 | | | | +---------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)用host50測試，只要下載mariadb即可，不需要mysql[root@host50 ~]# which mysql /usr/bin/which: no mysql in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin) [root@host50 ~]# yum -y install mariadb[root@host50 ~]# mysql -h192.168.4.53 -uadminuser -p123qqq...A MySQL [(none)]> create database gamedb; #創建測試庫 Query OK, 1 row affected (0.00 sec)MySQL [(none)]> create table gamedb.user(name char(10)); #在測試庫下創建user表 Query OK, 0 rows affected (0.07 sec)MySQL [(none)]> insert into gamedb.user values("bob"); #在表中插入數據 Query OK, 1 row affected (0.01 sec)MySQL [(none)]> quit Bye [root@host50 ~]# mysql -h192.168.4.54 -uadminuser -p123qqq...A -e "show databases" #驗證54主機的狀態 +--------------------+ | Database | +--------------------+ | information_schema | | gamedb | +--------------------+ [root@host50 ~]# mysql -h192.168.4.54 -uadminuser -p123qqq...A -e "select * from gamedb.user" #查詢插入的記錄 +------+ | name | +------+ | bob | +------+ [root@host50 ~]# mysql -h192.168.4.55 -uadminuser -p123qqq...A -e "show databases" #驗證55主機 +--------------------+ | Database | +--------------------+ | information_schema | | gamedb | +--------------------+ [root@host50 ~]# mysql -h192.168.4.55 -uadminuser -p123qqq...A -e "select * from gamedb.user" #查詢插入的表記錄 +------+ | name | +------+ | bob | +------+

配置主主模式

將數據庫服務器20、21配置為主主結構
20為主服務器 21為從服務器
20為從服務器 21為主服務器
在20、21上面都能看到啟動了binlog日志，以及slave status
互相同步對方的數據

1.準備環境：在兩臺主機上都要安裝mysql的軟件包 20主機： [root@20 ~]# ls mysql-5.7.17.tar [root@20 ~]# tar -xf mysql-5.7.17.tar [root@20 ~]# ls mysql-5.7.17.tar mysql-community-client-5.7.17-1.el7.x86_64.rpm mysql-community-common-5.7.17-1.el7.x86_64.rpm mysql-community-devel-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-compat-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-devel-5.7.17-1.el7.x86_64.rpm mysql-community-libs-5.7.17-1.el7.x86_64.rpm mysql-community-libs-compat-5.7.17-1.el7.x86_64.rpm mysql-community-minimal-debuginfo-5.7.17-1.el7.x86_64.rpm mysql-community-server-5.7.17-1.el7.x86_64.rpm mysql-community-test-5.7.17-1.el7.x86_64.rpm[root@20 ~]# systemctl stop firewalld [root@20 ~]# systemctl enable firewalld [root@20 ~]# yum -y install mysql-community*.rpm21主機： [root@21 ~]# ls mysql-5.7.17.tar [root@21 ~]# tar -xf mysql-5.7.17.tar [root@21 ~]# ls mysql-5.7.17.tar mysql-community-client-5.7.17-1.el7.x86_64.rpm mysql-community-common-5.7.17-1.el7.x86_64.rpm mysql-community-devel-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-compat-5.7.17-1.el7.x86_64.rpm mysql-community-embedded-devel-5.7.17-1.el7.x86_64.rpm mysql-community-libs-5.7.17-1.el7.x86_64.rpm mysql-community-libs-compat-5.7.17-1.el7.x86_64.rpm mysql-community-minimal-debuginfo-5.7.17-1.el7.x86_64.rpm mysql-community-server-5.7.17-1.el7.x86_64.rpm mysql-community-test-5.7.17-1.el7.x86_64.rpm[root@21 ~]# systemctl stop firewalld [root@21 ~]# systemctl enable firewalld [root@21 ~]# yum -y install mysql-community*.rpm2.起服務，修改密碼（兩臺主機做一樣的操作，以下以21為例）[root@21 ~]# ls /var/lib/mysql [root@21 ~]# systemctl start mysqld[root@21 ~]# ls /var/lib/mysql auto.cnf client-key.pem ib_logfile1 mysql.sock.lock server-cert.pem ca-key.pem ib_buffer_pool ibtmp1 performance_schema server-key.pem ca.pem ibdata1 mysql private_key.pem sys client-cert.pem ib_logfile0 mysql.sock public_key.pem[root@21 ~]# grep "password" /var/log/mysqld.log 2020-02-23T00:03:35.923408Z 1 [Note] A temporary password is generated for root@localhost: To5?l6Vphjee [root@21 ~]# mysql -uroot -p'To5?l6Vphjee' mysql> show variables like "%password%"; +---------------------------------------+--------+ | Variable_name | Value | +---------------------------------------+--------+ | default_password_lifetime | 0 | | disconnect_on_expired_password | ON | | log_builtin_as_identified_by_password | OFF | | mysql_native_password_proxy_users | OFF | | old_passwords | 0 | | report_password | | | sha256_password_proxy_users | OFF | | validate_password_check_user_name | OFF | | validate_password_dictionary_file | | | validate_password_length | 8 | | validate_password_mixed_case_count | 1 | | validate_password_number_count | 1 | | validate_password_policy | MEDIUM | | validate_password_special_char_count | 1 | +---------------------------------------+--------+ 14 rows in set (0.00 sec) mysql> set global validate_password_length=6; Query OK, 0 rows affected (0.00 sec)mysql> set global validate_password_policy=0; Query OK, 0 rows affected (0.00 sec)mysql> alter user root@"localhost" identified by "123456"; Query OK, 0 rows affected (0.00 sec)[root@21 ~]# vim /etc/my.cnf [mysqld] validate_password_length=6 validate_password_policy=0 [root@21 ~]# systemctl restart mysqld3.將20主機設為主服務器，21主機設為從服務器[root@20 ~]# vim /etc/my.cnf [mysqld] validate_password_length=6 validate_password_policy=0 server_id=20 log_bin=master20 [root@20 ~]# systemctl restart mysqld mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master20.000001 | 154 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)mysql> grant replication slave on *.* to tian@"%" identified by "123456"; Query OK, 0 rows affected, 1 warning (0.01 sec)mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master20.000001 | 437 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)[root@21 ~]# vim /etc/my.cnf [mysqld] validate_password_length=6 validate_password_policy=0 server_id=21[root@21 ~]# systemctl restart mysqld [root@21 ~]# mysql -uroot -p123456 mysql> show master status; Empty set (0.00 sec) mysql> change master to-> master_host="192.168.4.20",-> master_user="tian" ,-> master_password="123456" ,-> master_log_file="master20.000001" ,-> master_log_pos=437 ; Query OK, 0 rows affected, 2 warnings (0.01 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 eventMaster_Host: 192.168.4.20Master_User: tianMaster_Port: 3306Connect_Retry: 60Master_Log_File: master20.000001Read_Master_Log_Pos: 437Relay_Log_File: 21-relay-bin.000002Relay_Log_Pos: 319Relay_Master_Log_File: master20.000001Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 437Relay_Log_Space: 523Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 20Master_UUID: fd553082-55cf-11ea-a325-000c29fd476fMaster_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec)4.同樣，將21作為主服務器，20做為從服務器[root@21 ~]# vim /etc/my.cnf [mysqld] validate_password_length=6 validate_password_policy=0 server_id=21 log_bin=master21 [root@21 ~]# systemctl restart mysqld [root@21 ~]# mysql -uroot -p123456 mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master21.000002 | 154 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)mysql> grant replication slave on *.* to tian@"%" identified by "123456"; Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master21.000002 | 437 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)[root@20 ~]# mysql -uroot -p123456 mysql> change master to-> master_host="192.168.4.21" ,-> master_user="tian" ,-> master_password="123456" ,-> master_log_file="master21.000002" ,-> master_log_pos=437 ; Query OK, 0 rows affected, 2 warnings (0.03 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 eventMaster_Host: 192.168.4.21Master_User: tianMaster_Port: 3306Connect_Retry: 60Master_Log_File: master21.000002Read_Master_Log_Pos: 437Relay_Log_File: 20-relay-bin.000002Relay_Log_Pos: 319Relay_Master_Log_File: master21.000002Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 437Relay_Log_Space: 523Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 21Master_UUID: efdf9bdc-55cf-11ea-a2c4-000c293d6c33Master_Info_File: /var/lib/mysql/master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec)5.測試 在20主機上寫入數據，在21上也能查看，在21主機上寫入數據，在20主機上也能查看，且20與21主機同時都能查看到主服務器的binlog日志以及從服務器的信息20主機： mysql> create database aaa; Query OK, 1 row affected (0.00 sec)mysql> create table aaa.z(name char(10)); Query OK, 0 rows affected (0.02 sec)mysql> insert into aaa.z values("qqq"); Query OK, 1 row affected (0.04 sec)mysql> select * from aaa.z; +------+ | name | +------+ | qqq | +------+ 1 row in set (0.00 sec)21主機： mysql> select * from aaa.z; +------+ | name | +------+ | qqq | +------+ 1 row in set (0.00 sec)mysql> insert into aaa.z values("www"); Query OK, 1 row affected (0.01 sec)mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | +------+ 2 rows in set (0.00 sec) mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master21.000002 | 686 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)[root@21 ~]# ls /var/lib/mysql #查看mysql的目錄，發現出現了主庫信息以及中繼日志信息等 21-relay-bin.000001 client-cert.pem master21.000001 performance_schema 21-relay-bin.000002 client-key.pem master21.000002 private_key.pem 21-relay-bin.index ib_buffer_pool master21.index public_key.pem aaa ibdata1 master.info relay-log.info auto.cnf ib_logfile0 mysql server-cert.pem ca-key.pem ib_logfile1 mysql.sock server-key.pem ca.pem ibtmp1 mysql.sock.lock sys再次回到20主機查看：mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | +------+ 2 rows in set (0.00 sec) mysql> show master status; +-----------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +-----------------+----------+--------------+------------------+-------------------+ | master20.000001 | 1012 | | | | +-----------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)[root@20 ~]# ls /var/lib/mysql #20主機也有相應的主庫信息和中繼日志文件 20-relay-bin.000001 client-cert.pem master20.000001 private_key.pem 20-relay-bin.000002 client-key.pem master20.index public_key.pem 20-relay-bin.index ib_buffer_pool master.info relay-log.info aaa ibdata1 mysql server-cert.pem auto.cnf ib_logfile0 mysql.sock server-key.pem ca-key.pem ib_logfile1 mysql.sock.lock sys ca.pem ibtmp1 performance_schema也可以用客戶端進行測試： 在20與21主機上添加授權用戶： mysql> grant all on aaa.* to tian@"192.168.4.53" identified by "123456"; Query OK, 0 rows affected, 1 warning (0.01 sec) 客戶端登錄，分別在20與21主機的服務器上寫入數據： [root@host53 ~]# mysql -h192.168.4.20 -utian -p123456 mysql> show grants; +----------------------------------------------------------+ | Grants for tian@192.168.4.53 | +----------------------------------------------------------+ | GRANT USAGE ON *.* TO 'tian'@'192.168.4.53' | | GRANT ALL PRIVILEGES ON `aaa`.* TO 'tian'@'192.168.4.53' | +----------------------------------------------------------+ 2 rows in set (0.00 sec) mysql> insert into aaa.z values("sss"); Query OK, 1 row affected (0.01 sec)mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | | sss | +------+ 3 rows in set (0.00 sec)[root@host53 ~]# mysql -h192.168.4.21 -utian -p123456 mysql> insert into aaa.z values("eee"); Query OK, 1 row affected (0.01 sec)mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | | sss | | eee | +------+ 4 rows in set (0.00 sec)在20主機和21主機上分別查看： 20主機： mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | | sss | | eee | +------+ 4 rows in set (0.01 sec)21主機： mysql> select * from aaa.z; +------+ | name | +------+ | qqq | | www | | sss | | eee | +------+ 4 rows in set (0.00 sec)

復制模式

復制模式介紹

• 異步模式（Asynchronous replication）

• 主服務器執行完一次事務后，立即將結果返回給客戶端，不關心從服務器是否已經同步
• 如果配置一主多從模式，默認為異步模式，當客戶端寫入數據時，主服務器直接返回給客戶端告知數據已經存儲成功，而不等從服務器進行數據同步
• 好處：用戶的體驗度高
• 壞處：當主服務器壞掉時，有可能一個服務器上都沒有客戶端寫過的數據，造成數據丟失

• 半同步復制模式

• 介于異步復制和完全同步復制之間
• 主服務器在執行完一次事務后，等待至少一臺從服務器同步數據完成，才將結果返回給客戶端
• 當客戶端存儲數據時，只要有一臺從服務器同步主服務器的數據時，主服務器就會直接回復客戶端數據存儲已經完成，客戶端的體驗度高，也可以保證至少有一臺從服務器有同步數據

• 全同步復制模式

• 等所有的從服務器存儲完數據后，主服務器才回復給客戶端告知數據存儲完成，客戶端的體驗度低，但每個從服務器中都有主服務器中的數據，當主服務器壞掉也可以正常使用

配置半同步模式

- 步驟： 1. 安裝模塊 2. 查看安裝模塊 3. 啟用模塊 命令行配置（馬上生效，但重啟服務會失效）host53主 查看是否允許動態加載模塊（默認允許） mysql> show variables like "have_dynamic_loading"; +----------------------+-------+ | Variable_name | Value | +----------------------+-------+ | have_dynamic_loading | YES | +----------------------+-------+ 1 row in set (0.03 sec)命令行安裝模塊 mysql> install plugin rpl_semi_sync_master soname "semisync_master.so"; Query OK, 0 rows affected (0.07 sec)查看模塊 mysql> use information_schema mysql> desc PLUGINS; +------------------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------+-------------+------+-----+---------+-------+ | PLUGIN_NAME | varchar(64) | NO | | | | | PLUGIN_VERSION | varchar(20) | NO | | | | | PLUGIN_STATUS | varchar(10) | NO | | | | | PLUGIN_TYPE | varchar(80) | NO | | | | | PLUGIN_TYPE_VERSION | varchar(20) | NO | | | | | PLUGIN_LIBRARY | varchar(64) | YES | | NULL | | | PLUGIN_LIBRARY_VERSION | varchar(20) | YES | | NULL | | | PLUGIN_AUTHOR | varchar(64) | YES | | NULL | | | PLUGIN_DESCRIPTION | longtext | YES | | NULL | | | PLUGIN_LICENSE | varchar(80) | YES | | NULL | | | LOAD_OPTION | varchar(64) | NO | | | | +------------------------+-------------+------+-----+---------+-------+ 11 rows in set (0.00 sec) 查看模塊是否安裝成功 mysql> select PLUGIN_NAME , PLUGIN_STATUS from PLUGINS where PLUGIN_NAME like "%semi%"; +----------------------+---------------+ | plugin_name | plugin_status | +----------------------+---------------+ | rpl_semi_sync_master | ACTIVE | +----------------------+---------------+ 1 row in set (0.00 sec)啟用master半同步復制模式 mysql> set global rpl_semi_sync_master_enabled=1; Query OK, 0 rows affected (0.01 sec)查看半同步復制模式是否已啟用 mysql> show variables like "rpl_semi_sync_%_enabled"; +------------------------------+-------+ | Variable_name | Value | +------------------------------+-------+ | rpl_semi_sync_master_enabled | ON | +------------------------------+-------+ 1 row in set (0.24 sec)host54主從 安裝模塊 主： mysql> install plugin rpl_semi_sync_master soname "semisync_master.so"; Query OK, 0 rows affected (0.08 sec)從： mysql> install plugin rpl_semi_sync_slave soname "semisync_slave.so"; Query OK, 0 rows affected (0.03 sec)mysql> use information_schema mysql> select plugin_name ,plugin_status from plugins where plugin_name like "%semi%" ; +----------------------+---------------+ | plugin_name | plugin_status | +----------------------+---------------+ | rpl_semi_sync_master | ACTIVE | | rpl_semi_sync_slave | ACTIVE | +----------------------+---------------+ 2 rows in set (0.10 sec)mysql> set global rpl_semi_sync_master_enabled=1; Query OK, 0 rows affected (0.10 sec)mysql> set global rpl_semi_sync_slave_enabled=1; Query OK, 0 rows affected (0.00 sec)mysql> show variables like "rpl_semi_sync_%_enabled"; +------------------------------+-------+ | Variable_name | Value | +------------------------------+-------+ | rpl_semi_sync_master_enabled | ON | | rpl_semi_sync_slave_enabled | ON | +------------------------------+-------+ 2 rows in set (0.09 sec)host55從mysql> install plugin rpl_semi_sync_slave soname "semisync_slave.so"; Query OK, 0 rows affected (0.06 sec) mysql> use information_schema mysql> select plugin_name ,plugin_status from plugins where plugin_name like "%semi%" ; +---------------------+---------------+ | plugin_name | plugin_status | +---------------------+---------------+ | rpl_semi_sync_slave | ACTIVE | +---------------------+---------------+ 1 row in set (0.00 sec)mysql> set global rpl_semi_sync_slave_enabled=1; Query OK, 0 rows affected (0.00 sec)mysql> show variables like "rpl_semi_sync_%_enabled"; +-----------------------------+-------+ | Variable_name | Value | +-----------------------------+-------+ | rpl_semi_sync_slave_enabled | ON | +-----------------------------+-------+ 1 row in set (0.01 sec)************************************************************ 永久配置（/etc/my.cnf） 在host54主機上面操作，永久啟用半同步復制模式[root@host54 mysql]# vim /etc/my.cnf [mysqld] server_id=54 log_bin=host54 log_slave_updates plugin-load="rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so" rpl_semi_sync_master_enabled=1 rpl_semi_sync_slave_enabled=1重啟數據庫服務，并查看狀態信息[root@host54 mysql]# mystemctl restart mysqld [root@host54 mysql]# mysql -uroot -p123456 mysql> select plugin_name, plugin_status from information_schema.plugins where plugin_name like '%semi%'; +----------------------+---------------+ | plugin_name | plugin_status | +----------------------+---------------+ | rpl_semi_sync_master | ACTIVE | //模塊已加載 | rpl_semi_sync_slave | ACTIVE | +----------------------+---------------+ 2 rows in set (0.00 sec) mysql> show variables like "rpl_semi_sync_%_enabled"; +------------------------------+-------+ | Variable_name | Value | +------------------------------+-------+ | rpl_semi_sync_master_enabled | ON | //模式已啟用 | rpl_semi_sync_slave_enabled | ON | +------------------------------+-------+ 2 rows in set (0.00 sec)

總結

• 主從復制的用途

• 實時備份，用于故障切換
• 讀寫分離，提供查詢服務
• 備份，避免影響業務

• 主從部署的必要條件？

• 主庫開啟binlog日志（設置binlog參數）
• 主從server_id不同
• 從庫服務器要與主庫數據相同，可以連通主庫

• 主從復制存在的問題？

• 主庫宕機后，數據可能會丟失
• 從庫只有一個SQL Thread，主庫寫的壓力大，復制可能會延時
• 解決辦法：
• 半同步復制，可以解決數據丟失的問題

總結

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