mysql5.6 主从同步

时间:2021-12-22 12:08:08

主库IP:192.168.220.3

从库IP:192.168.220.4


1、主库配置编辑my.cnf:

# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
# *** DO NOT EDIT THIS FILE. It's a template which will be copied to the
# *** default location during install, and will be replaced if you
# *** upgrade to a newer version of MySQL. [mysqld] # Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at % of total RAM for dedicated server, else %.
# innodb_buffer_pool_size = 128M # Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin # These are commonly set, remove the # and set as required.
basedir = /usr/mysql
datadir = /usr/mysql/data
port =
server_id =
socket = /tmp/mysql.sock
lower_case_table_names = log-bin = mysql-bin # 启用二进制日志
server-id = # 服务器唯一ID 取IP最后一段
sync_binlog = # 每次事务提交则将cache中的数据写入磁盘并同步执行同步指令,此时最安全但是性能损失最大
binlog_format = mixed # binlog日志格式,mysql默认采用
binlog-do-db = db1 # 同步数据库
binlog-ignore-db = mysql # 忽略同步的数据库
binlog-ignore-db = performance_schema
binlog-ignore-db = information_schema
binlog_checksum=NONE # Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

2、主库mysql创建同步账号

grant replication slave on *.* to slave@192.168.220.4 indentified by 'qwe123'

flush privileges;

3、主库状态

mysql> show master status;

+------------------+----------+--------------+---------------------------------------------+-------------------+
| File                      | Position | Binlog_Do_DB | Binlog_Ignore_DB                                           | Executed_Gtid_Set |
+------------------+----------+--------------+---------------------------------------------+-------------------+
| mysql-bin.000002 |      402 | db1                 | mysql,performance_schema,information_schema |                   |
+------------------+----------+--------------+---------------------------------------------+-------------------+

记录下二进制日志文件名和位置


4、从库配置文件配置

# 启用二进制日志
log-bin=mysql-bin
# 服务器唯一ID,一般取IP最后一段
server-id= relay-log-index = slave-relay-bin.index relay-log = slave-relay-bin sync_master_info = sync_relay_log = sync_relay_log_info =

5、从库mysql中配置连接主库

change master to master_host='192.168.220.3',master_user='slave',master_password='qwe123', master_log_file='mysql-bin.000002',master_log_pos=402;

6、开始同步

mysql> start slave;

7、查看同步状态

mysql> show slave status\G;

Slave_IO_Running: Yes
Slave_SQL_Running: Yes


备注:如果主从不同步处理方案

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

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@192.168.220.4:/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 = '192.168.220.3', master_user = 'slave', master_port=3306, master_password='qwe123', 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