MySQL5.7主從從配置
主從從，也稱為級聯主從，數據流向：A(主)->B(從)->C(從從)，主從從級聯復制。
應用場景
- 在主從配置的基礎上，再增加一個從庫，進一步提高數據安全，容災備份。
- 讀寫分離，從庫只用於查詢，提高數據庫整體性能。
- 從從庫，用於備份，等同在線實時增量備份。
部署環境
注：使用docker部署mysql實例，方便快速搭建演示環境。但本文重點是講解主從配置，因此簡略描述docker環境構建mysql容器實例。
- 數據庫：MySQL 5.7.x （相比5.5，5.6而言，5.7同步性能更好，支持多源復制，可實現多主一從，主從庫版本應保證一致）
- 操作系統：CentOS 7.x
- 容器：Docker 17.09.0-ce
- 鏡像：mysql:5.7
- 主庫：IP=192.168.10.212; PORT=4200; server-id=200; database=test; table=user
- 從庫：IP=192.168.10.212; PORT=4211; server-id=210; database=test; table=user
- 從從庫：IP=192.168.10.212; PORT=4211; server-id=211; database=test; table=userk
配置約束
- 主從庫必須保證網絡暢通可訪問
- 主庫必須開啟binlog日志
- 主從庫的server-id必須不同
事前准備
- 關閉selinux
setenforce 0
vim /etc/sysconfig/selinux
SELINUX=disabled
# 若不關閉，使用docker啟動mysql5.7鏡像容器時啟動不起來，查看日志會有如下錯誤顯示： ERROR: mysqld failed while attempting to check config command was: "mysqld --verbose --help" mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 13 - Permission denied) mysqld: [ERROR] Fatal error in defaults handling. Program aborted! ERROR: mysqld failed while attempting to check config command was: "mysqld --verbose --help" mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 13 - Permission denied) mysqld: [ERROR] Fatal error in defaults handling. Program aborted! - 安裝並啟動docker
yum install epel-release
yum -y install docker
systemctl start docker.service
- 創建目錄
mkdir -p /datavol/mysql-200/{mysql,conf}
mkdir -p /datavol/mysql-210/{mysql,conf}
mkdir -p /datavol/mysql-211/{mysql,conf}
【主庫】操作及配置
把該文件放到主庫所在配置文件路徑下：/datavol/mysql-200/conf
配置my.cnf
[client] port = 3306 default-character-set = utf8mb4 [mysql] port = 3306 default-character-set = utf8mb4 [mysqld] ########################## # summary ########################## #bind-address = 0.0.0.0 #port = 3306 #datadir=/datavol/mysql/data #數據存儲目錄 ########################## # log bin ########################## server-id = 200 #必須唯一 log_bin = mysql-bin #開啟及設置二進制日志文件名稱 binlog_format = MIXED sync_binlog = 1 expire_logs_days =7 #二進制日志自動刪除/過期的天數。默認值為0，表示不自動刪除。 #binlog_cache_size = 128m #max_binlog_cache_size = 512m #max_binlog_size = 256M binlog-do-db = test #要同步的數據庫 binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schema binlog_ignore_db = performation_schema binlog_ignore_db = sys ########################## # character set ########################## character-set-server = utf8mb4 collation-server = utf8mb4_unicode_ci 安裝啟動主庫
[root@localhost ~]# docker run -d -p 4200:3306 --name=mysql-200 -v /datavol/mysql-200/conf:/etc/mysql/conf.d -v /datavol/mysql-200:/datavol/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7 5691bac538e646db00273e3cad5b350dbe6cce0bd176346b7eefd9a6f9e3a9ad [root@localhost ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 5691bac538e6 mysql:5.7 "docker-entrypoint..." 44 seconds ago Up 43 seconds 33060/tcp, 0.0.0.0:4200->3306/tcp mysql-200 [root@localhost ~]# docker exec -it mysql-200 /bin/bash root@5691bac538e6:/# mysql -u root -p Enter password: 注：若不熟悉docker，可使用傳統方式安裝mysql，效果相同。
創建授權用戶
連接mysql主數據庫，鍵入命令mysql -u root -p，輸入密碼后登錄數據庫。創建用戶用於從庫同步復制，授予復制、同步訪問的權限
mysql> CREATE USER 'slave'@'%' IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.01 sec) mysql> GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'%'; Query OK, 0 rows affected (0.00 sec) log_bin是否開啟
mysql> show variables like 'log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin | ON | +---------------+-------+ 1 row in set 查看master狀態
mysql> show master status;
+------------------+----------+--------------+--------------------------------------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+--------------------------------------------------+-------------------+ | mysql-bin.000001 | 154 | test | mysql,information_schema,performation_schema,sys | | +------------------+----------+--------------+--------------------------------------------------+-------------------+ 1 row in set 【從庫】配置及操作
配置my.cnf
把該文件放到主庫所在配置文件路徑下：/datavol/mysql-210/conf/
[client] port = 3306 default-character-set = utf8mb4 [mysql] port = 3306 default-character-set = utf8mb4 [mysqld] ########################## # summary ########################## #bind-address = 0.0.0.0 #port = 3306 #datadir=/datavol/mysql/data #數據存儲目錄 ########################## # log bin ########################## server-id = 210 #必須唯一 log_bin = mysql-bin #開啟及設置二進制日志文件名稱 binlog_format = MIXED sync_binlog = 1 expire_logs_days =7 #二進制日志自動刪除/過期的天數。默認值為0，表示不自動刪除。 log_slave_updates = 1 #【關鍵點】從主服務器接收到的更新同時要寫入二進制日志 #binlog_cache_size = 128m #max_binlog_cache_size = 512m #max_binlog_size = 256M binlog-do-db = test #要同步的數據庫 binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schema binlog_ignore_db = performation_schema binlog_ignore_db = sys ########################## # character set ########################## character-set-server = utf8mb4 collation-server = utf8mb4_unicode_ci **log_slave_updates = 1 ** #【關鍵點】從主服務器接收到的更新同時要寫入二進制日志
啟動前確認slave賬號在備庫服務器上，是否能夠正常連接主庫，檢查權限。
命令：mysql -h 主庫ip -u slave -p；輸入密碼確認登錄情況；
安裝啟動從庫
[root@localhost ~]# docker run -d -p 4210:3306 --name=mysql-210 -v /datavol/mysql-210/conf:/etc/mysql/conf.d -v /datavol/mysql-210:/datavol/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7 19e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7 [root@localhost ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 19e93b6d93ca mysql:5.7 "docker-entrypoint..." 4 seconds ago Up 3 seconds 33060/tcp, 0.0.0.0:4210->3306/tcp mysql-210 [root@localhost ~]# docker exec -it mysql-210 /bin/bash root@19e93b6d93ca:/# mysql -u root -p Enter password: 設置主庫200信息
登錄【從數據庫】，進入mysql命令行。
mysql> stop slave;
Query OK, 0 rows affected
mysql> CHANGE MASTER TO
MASTER_HOST='192.168.10.212',
MASTER_PORT=4200,
MASTER_USER='slave',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000001',
MASTER_LOG_POS=154;
Query OK, 0 rows affected
mysql> start slave;
Query OK, 0 rows affected
stop slave; //停止同步
start slave; //開始同步
//必須和【主數據庫】的信息匹配。
CHANGE MASTER TO
MASTER_HOST='192.168.10.212', //主庫IP
MASTER_PORT=4200, //主庫端口
MASTER_USER='slave', //訪問主庫且有同步復制權限的用戶
MASTER_PASSWORD='123456', //登錄密碼
//【關鍵處】從主庫的該log_bin文件開始讀取同步信息，主庫show master status返回結果
MASTER_LOG_FILE='mysql-bin.000001',
//【關鍵處】從文件中指定位置開始讀取，主庫show master status返回結果
MASTER_LOG_POS=154;
查看同步狀態
mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.10.212 Master_User: slave Master_Port: 4200 Connect_Retry: 60 Master_Log_File: mysql-bin.000003 Read_Master_Log_Pos: 617 Relay_Log_File: 5f0d9861bcb1-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: 617 Relay_Log_Space: 534 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: 200 Master_UUID: b6df98cf-e71f-11e8-9987-0242ac110007 Master_Info_File: /var/lib/mysql/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) 只有【Slave_IO_Running】和【Slave_SQL_Running】都是Yes，則同步是正常的。
如果是No或者Connecting都不行，可查看mysql-error.log，以排查問題。
mysql> show variables like 'log_error%'; +---------------------+--------+ | Variable_name | Value | +---------------------+--------+ | log_error | stderr | | log_error_verbosity | 3 | +---------------------+--------+ 2 rows in set 配置完成，則主從數據庫開始自動同步。此外，【從庫】相當於【從從庫】的主庫，也需要設置賬號及同步權限。
創建授權用戶
創建用戶用於從庫同步復制，授予復制、同步訪問的權限
mysql> CREATE USER 'slave'@'%' IDENTIFIED BY '123456'; Query OK, 0 rows affected (0.01 sec) mysql> GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave'@'%'; Query OK, 0 rows affected (0.00 sec) log_bin是否開啟
mysql> show variables like 'log_bin'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_bin | ON | +---------------+-------+ 1 row in set 查看master狀態
mysql> show master status;
+------------------+----------+--------------+--------------------------------------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+--------------------------------------------------+-------------------+ | mysql-bin.000003 | 617 | test | mysql,information_schema,performation_schema,sys | | +------------------+----------+--------------+--------------------------------------------------+-------------------+ 1 row in set 【從從庫】配置及操作
配置my.cnf
把該文件放到主庫所在配置文件路徑下：/datavol/mysql-211/conf/
[client]
port = 3306 default-character-set = utf8mb4 [mysql] port = 3306 default-character-set = utf8mb4 [mysqld] ########################## # summary ########################## #bind-address = 0.0.0.0 #port = 3306 #datadir=/datavol/mysql/data #數據存儲目錄 ########################## # log bin ########################## server-id = 211 ########################## # character set ########################## character-set-server = utf8mb4 collation-server = utf8mb4_unicode_ci 安裝啟動從從庫
[root@localhost ~]# docker run -d -p 4211:3306 --name=mysql-211 -v /datavol/mysql-211/conf:/etc/mysql/conf.d -v /datavol/mysql-211:/datavol/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7 19e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7 [root@localhost ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 19e93b6d93ca mysql:5.7 "docker-entrypoint..." 4 seconds ago Up 3 seconds 33060/tcp, 0.0.0.0:4211->3306/tcp mysql-211 [root@localhost ~]# docker exec -it mysql-211 /bin/bash root@19e93b6d93ca:/# mysql -u root -p Enter password: 設置從庫210信息
登錄【從數據庫】，進入mysql命令行。
mysql> stop slave;
Query OK, 0 rows affected
mysql> CHANGE MASTER TO MASTER_HOST='192.168.10.212',
MASTER_PORT=4210,
MASTER_USER='slave',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000003',
MASTER_LOG_POS=617;
Query OK, 0 rows affected
mysql> start slave;
Query OK, 0 rows affected
stop slave; //停止同步
start slave; //開始同步
//必須和【主數據庫】的信息匹配。
CHANGE MASTER TO
MASTER_HOST='192.168.10.212', //主庫IP
MASTER_PORT=4210, //主庫端口(在這里是指從庫)
MASTER_USER='slave', //訪問主庫且有同步復制權限的用戶
MASTER_PASSWORD='123456', //登錄密碼
//【關鍵處】從主庫的該log_bin文件開始讀取同步信息，重啟mysql服務后，主庫show master status返回結果，
MASTER_LOG_FILE='mysql-bin.000003',
//【關鍵處】從文件中指定位置開始讀取，重啟mysql服務后，主庫show master status返回結果，重新取值
MASTER_LOG_POS=617;
查看同步狀態
mysql> show slave status \G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.10.212 Master_User: slave Master_Port: 4210 Connect_Retry: 60 Master_Log_File: mysql-bin.000003 Read_Master_Log_Pos: 617 Relay_Log_File: a3d52e314640-relay-bin.000002 Relay_Log_Pos: 783 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: 617 Relay_Log_Space: 997 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: 210 Master_UUID: 088c2c93-e720-11e8-8e80-0242ac110009 Master_Info_File: /var/lib/mysql/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) 只有【Slave_IO_Running】和【Slave_SQL_Running】都是Yes，則同步是正常的。
如果是No或者Connecting都不行，可查看mysql-error.log，以排查問題。
mysql> show variables like 'log_error%'; +---------------------+--------+ | Variable_name | Value | +---------------------+--------+ | log_error | stderr | | log_error_verbosity | 3 | +---------------------+--------+ 2 rows in set 配置完成，則從從數據庫開始自動同步。
驗證數據同步
建庫
使用root賬號登錄【主服務器】，創建test數據庫
mysql> CREATE DATABASE test; Query OK, 1 row affected (0.00 sec) mysql> USE test; Database changed 建表
在【主庫】中創建user表
CREATE TABLE `user` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `name` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL, `age` tinyint(3) unsigned NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci; 新增
在【主庫】中向user表插入一條數據：
mysql> use test; Database changed mysql> INSERT INTO user (id, name, age) VALUES (1, '張三', 18); Database changed mysql> SELECT * FROM user; +----+------+-----+ | id | name | age | +----+------+-----+ | 1 | 張三 | 18 | +----+------+-----+ 1 row in set 在【從庫】及【從從庫】中查詢user表數據：
mysql> use test; Database changed mysql> SELECT * FROM user; +----+------+-----+ | id | name | age | +----+------+-----+ | 1 | 張三 | 18 | +----+------+-----+ 1 row in set 新增記錄同步成功。
更新
在【主庫】中修改剛才插入的數據：
mysql> UPDATE user SET name='李四' where id=1; Database changed Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT * FROM user; +----+------+-----+ | id | name | age | +----+------+-----+ | 1 | 李四 | 18 | +----+------+-----+ 1 row in set 在【從庫】及【從從庫】中查詢user表數據：
mysql> SELECT * FROM user;
+----+------+-----+
| id | name | age | +----+------+-----+ | 1 | 李四 | 18 | +----+------+-----+ 1 row in set 更新記錄同步成功。
刪除
在【主庫】中刪除剛才更新的數據：
mysql> DELETE FROM user WHERE id=1; Database changed mysql> SELECT * FROM user; Empty set 在【從庫】及【從從庫】中查詢user表數據：
mysql> SELECT * FROM user; Empty set 刪除記錄同步成功。
補充：
- 如果【主服務器】重啟mysql服務，【從服務器】會等待與【主服務器】重連。當主服務器恢復正常后，從服務器會自動重新連接上主服務器，並正常同步數據。
- 如果某段時間內，【從數據庫】服務器異常導致同步中斷（可能是同步點位置不匹配），可以嘗試以下恢復方法：進入【主數據庫】服務器（正常），在bin-log中找到【從數據庫】出錯前的position，然后在【從數據庫】上執行change master，將master_log_file和master_log_pos重新指定后，開始同步。
- 以上為參考：
- 實際搭建環境為window服務器器，my.ini的配置如下：搭建主從負載前,主、備服務器，已建數據庫efb，經過測試可以實現主從復制。
- master示例：
-
###### CLIENT SECTION ###### # The following options will be read by MySQL client applications. # Note that only client applications shipped by MySQL are guaranteed # to read this section. If you want your own MySQL client program to # honor these values, you need to specify it as an option during the # MySQL client library initialization. [client] port=3306 [mysql] default-character-set=utf8 ###### SERVER SECITON ###### # The following options will be read by the MySQL Server. Make sure that # you have installed the server correctly (see above) so it reads this # file. [mysqld] #skip-grant-tables # The TCP/IP Port the MySQL Server will listen on port = 3306 #Path to installation directory. All paths are usually resolved relative to this. basedir=D:\Program Files\mysql-5.7.26-winx64 #Path to the database root datadir=D:\Program Files\mysql-5.7.26-winx64\data # The default character set that will be used when a new schema or table is # created and no character set is defined character-set-server=utf8 # The maximum amount of concurrent sessions the MySQL server will # allow. One of these connections will be reserved for a user with # SUPER privileges to allow the administrator to login even if the # connection limit has been reached. max_connections=200 bind-address=0.0.0.0 # The default storage engine that will be used when create new tables when default-storage-engine=INNODB # Set the SQL mode to strict sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES # 慢查詢時間 超過3秒則為慢查詢 slow_query_log = 1 long_query_time = 3 slow-query-log-file = D:\Program Files\mysql-5.7.26-winx64\log\mysql-slow.log # 錯誤日志路徑 log_error = D:\Program Files\mysql-5.7.26-winx64\log\mysql-error.log ###### 主從配置 MASTER-SLAVE ###### # 節點ID，確保唯一 server-id = 885 #開啟mysql的binlog日志功能 log-bin = mysql-bin #控制數據庫的binlog刷到磁盤上去 , 0 不控制，性能最好，1每次事物提交都會刷到日志文件中，性能最差，最安全 sync_binlog = 1 #binlog日志格式，mysql默認采用statement，建議使用mixed binlog_format = mixed #binlog過期清理時間 expire_logs_days = 30 #binlog每個日志文件大小 max_binlog_size = 1000m #binlog緩存大小 binlog_cache_size = 4m #最大binlog緩存大 max_binlog_cache_size= 512m #要同步的數據庫 binlog-do-db = efb #不生成日志文件的數據庫，多個忽略數據庫可以用逗號拼接，或者 復制這句話，寫多行 binlog-ignore-db=mysql binlog_ignore_db = information_schema binlog_ignore_db = performation_schema binlog_ignore_db = sys # 自增值的偏移量 auto-increment-offset = 1 # 自增值的自增量 auto-increment-increment = 1 #跳過從庫錯誤 slave-skip-errors = all
slave示例：
[client] port = 3306 default-character-set=utf8 [mysql] port = 3306 default-character-set=utf8 [mysqld] port = 3306 character-set-server=utf8 basedir=D:\Program Files\mysql-5.7.26-winx64 datadir=D:\Program Files\mysql-5.7.26-winx64\data max_connections=200 default-storage-engine=INNODB sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES ###slave### server-id = 890 #必須唯一 log_bin = mysql-bin #開啟及設置二進制日志文件名稱 binlog_format = MIXED sync_binlog = 1 expire_logs_days =7 #二進制日志自動刪除/過期的天數。默認值為0，表示不自動刪除。 log_slave_updates = 1 #【關鍵點】從主服務器接收到的更新同時要寫入二進制日志 #binlog_cache_size = 128m #max_binlog_cache_size = 512m #max_binlog_size = 256M binlog-do-db = efb #要同步的數據庫 binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schema binlog_ignore_db = performation_schema binlog_ignore_db = sys