Mysql 5.6主从同步配置与解决方案
主库IP:192.168.1.10
从库IP:192.168.1.11
centos的mysql配置文件在:/etc/my.cnf
1、主库配置编辑my.cnf:
# 启用二进制日志
log_bin = mysql-bin
server-id = 111 //唯一编号,默认1,一般写IP最后3位
log-bin-index=mysql-bin.index
sync_binlog=1
binlog_format=mixed
binlog-do-db = testdb //同步数据库
binlog-ignore-db = mysql
binlog-ignore-db = performance_schema
binlog-ignore-db = information_schema
binlog_checksum=NONE
2、创建同步账号(赋予同步权限)
grant replication slave on *.* to 'user'@'192.168.1.11' identified by '123456'
3、主库状态
mysql> flush privileges;
mysql> show master status;
+------------------+----------+-------------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+-------------------+------------------+-------------------+
| mysql-bin.000009 | 199 | my_database | | |
+------------------+----------+-------------------+------------------+-------------------+
记录下二进制日志文件名和位置
4、从库配置文件配置
# [必须]启用二进制日志
log-bin=mysql-bin
# [必须]服务器唯一ID,默认是1,一般取IP最后一段
server-id=222
relay-log-index = slave-relay-bin.index
relay-log = slave-relay-bin
sync_master_info = 1
sync_relay_log = 1
sync_relay_log_info = 1
5、配置连接主库(从库使用自己mysql的账号登录)
mysql -u root -p 123456
然后执行同步命令
mysql> change master to master_host='192.168.1.10',master_user='slave',master_password='123456', master_log_file='mysql-bin.000009',master_log_pos=199;
6、开始同步
mysql> start slave;
mysql> show slave status\G;
7、正常状态
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
如果提示
Last_IO_Error: error reconnecting to master 'user@192.168.1.10:3306' - retry-time: 60 retries: 1
说明权限不够,在主数据库中执行:
grant replication slave on *.* to 'user'@'192.168.1.10';
8、解决主从不同步
先上Master库:
mysql>show processlist; 查看下进程是否Sleep太多。发现很正常。
show master status; 也正常。
mysql> show master status;
+-------------------+----------+--------------+-------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------------+----------+--------------+-------------------------------+
| mysqld-bin.000001 | 3260 | | mysql,test,information_schema |
+-------------------+----------+--------------+-------------------------------+
1 row in set (0.00 sec)
再到Slave上查看
mysql> show slave status\G
Slave_IO_Running: Yes
Slave_SQL_Running: No
可见是Slave不同步
下面介绍两种解决方法:
方法一:忽略错误后,继续同步
该方法适用于主从库数据相差不大,或者要求数据可以不完全统一的情况,数据要求不严格的情况
解决:
stop slave;
#表示跳过一步错误,后面的数字可变
set global sql_slave_skip_counter =1;
start slave;
之后再用mysql> show slave status\G 查看:
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
ok,现在主从同步状态正常
方式二:重新做主从,完全同步
该方法适用于主从库数据相差较大,或者要求数据完全统一的情况
解决步骤如下:
1.先进入主库,进行锁表,防止数据写入
使用命令:
mysql> flush tables with read lock;
注意:该处是锁定为只读状态,语句不区分大小写
2.进行数据备份
#把数据备份到mysql.bak.sql文件
[root@server01 mysql]#mysqldump -uroot -p -hlocalhost > mysql.bak.sql
这里注意一点:数据库备份一定要定期进行,确保数据万无一失
3.查看master 状态
mysql> show master status;
+-------------------+----------+--------------+-------------------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+-------------------+----------+--------------+-------------------------------+
| mysqld-bin.000001 | 3260 | | mysql,test,information_schema |
+-------------------+----------+--------------+-------------------------------+
1 row in set (0.00 sec)
4.把mysql备份文件传到从库机器,进行数据恢复
#使用scp命令
[root@server01 mysql]# scp mysql.bak.sql root@192.168.128.11:/tmp/
5.停止从库的状态
mysql> stop slave;
6.然后到从库执行mysql命令,导入数据备份
mysql> source /tmp/mysql.bak.sql
7.设置从库同步,注意该处的同步点,就是主库show master status信息里的| File| Position两项
change master to master_host = '192.168.128.10', master_user = 'slave', master_port=3306, master_password='123456', master_log_file = 'mysqld-bin.000001', master_log_pos=3260;
8.重新开启从同步
mysql> start slave;
9.查看同步状态
mysql> show slave status\G 查看:
Slave_IO_Running: Yes
Slave_SQL_Running: Yes