Mysql 主从复制
参考自 https://www.jianshu.com/p/faf0127f1cb2
yum install -y mariadb-server
systemctl enable mariadb&&systemctl restart mariadb
主端
vim /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
#-----------------------------加入如下行------------------------------
server_id=38
log-bin=mysql-bin
#-------------------------------------------------------
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
重启
systemctl restart mariadb
验证是否已经配置成功
能够查询对应配置文件中的server_id 说明已经配置成功，如下图，则表示配置成功。server_id=38
MariaDB [mysql]> show variables like '%server_id%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| server_id | 38 |
+---------------+-------+
1 row in set (0.00 sec)
show master status;
# 能够看到同步的文件，和行数说明已经配置成功。
MariaDB [mysql]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000004 | 729 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
锁定主端数据库
flush tables with read unlock;
# 先锁住主端数据库，禁止读写，防止出现gap
# 待备端配好后 UNLOCK TABLES; 解锁主端数据库
从端
vi /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
server_id=39
# 配置服务器id server_id
# 这里的server_id 尽量配置为服务器地址的后3位 以用来区分
log-bin=mysql-bin
# 开启日志文件(binLog)
binlog_do_db=test
# 添加需用同步的数据库,不添加这一行则同步所有的数据库
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
从服务器同步主服务器配置
master_host 主服务器地址 master_user 主服务器用户名 master_password 主服务器密码 master_log_file 主服务器配置文件 master_log_pos 主服务器读取配置文件的开始位置，也就是从第多少行开始读取。
MariaDB [mysql]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000004 | 729 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
# File字段代表日志文件
# Position字段代表开始读取的行数
# 从服务器同步主服务器配置
change master to master_host='172.16.102.38',master_user='root',master_password='123456',master_log_file='mysql-bin.000004',master_log_pos=729;
MariaDB [mysql]> change master to master_host='172.16.102.38',master_user='root',master_password='123456',master_log_file='mysql-bin.000004',master_log_pos=729;
Query OK, 0 rows affected (0.01 sec)
change master to master_host='172.16.102.38',master_user='root',master_password='123456',master_log_file='mysql-bin.000005',master_log_pos=245;
# 开始同步
start slave;
# 关闭同步
stop slave;
解锁主端数据库
UNLOCK TABLES;
# 解锁主端数据库
在从站上暂停复制
您可以使用
要停止从主服务器处理二进制日志，请使用
mysql> STOP SLAVE;
当复制停止时，从I / O线程停止从主二进制日志读取事件并将它们写入中继日志，并且SQL线程停止从中继日志读取事件并执行它们。您可以通过指定线程类型单独暂停I / O或SQL线程：
mysql> STOP SLAVE IO_THREAD;
mysql> STOP SLAVE SQL_THREAD;
要再次开始执行，请使用以下
mysql> START SLAVE;
要启动特定线程，请指定线程类型：
mysql> START SLAVE IO_THREAD;
mysql> START SLAVE SQL_THREAD;
排错
# 检查从服务器复制功能状态，Slave_IO_Running，Slave_SQL_Running必须为YES才行。
SHOW SLAVE STATUS\G;
MariaDB [mysql]> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State: Connecting to master
Master_Host: 172.16.102.38
Master_User: root
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000004
Read_Master_Log_Pos: 729
Relay_Log_File: mariadb-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-bin.000004
Slave_IO_Running: Connecting
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: 729
Relay_Log_Space: 245
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: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 1045
Last_IO_Error: error connecting to master 'root@172.16.102.38:3306' - retry-time: 60 retries: 86400 message: Access denied for user 'root'@'HDSS7-21' (using password: YES)
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 0
1 row in set (0.00 sec)
ERROR: No query specified
#Slave_IO_Running显示Connecting原因：
#防火墙没关
#密码不对
#主数据库无法连接
#总之就是连不上主库，备库一直在尝试Connecting
如果出现Slave_SQL_Running为No错误
MariaDB [mysql]> show slave status\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.102.38
Master_User: root
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000005
Read_Master_Log_Pos: 2854
Relay_Log_File: mariadb-relay-bin.000002
Relay_Log_Pos: 800
Relay_Master_Log_File: mysql-bin.000005
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1051
Last_Error: Error 'Unknown table 't'' on query. Default database: 'test'. Query: 'DROP TABLE `t` /* generated by server */'
Skip_Counter: 0
Exec_Master_Log_Pos: 516
Relay_Log_Space: 4594
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: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1051
Last_SQL_Error: Error 'Unknown table 't'' on query. Default database: 'test'. Query: 'DROP TABLE `t` /* generated by server */'
Replicate_Ignore_Server_Ids:
Master_Server_Id: 38
1 row in set (0.00 sec)
ERROR: No query specified
多次执行以下语句就好
stop slave;
set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
start slave;
