使用mysqldump搭建主从库
文章目录
- my.cnf参数前提条件
-
-
- 参数配置情况
-
- 使用mysqldump备份
-
- 备份
- 参数说明
- 备份文件传给从库
- 恢复数据
-
- 报错-1
- 报错-1: 解决办法
- 报错-2
- 报错-2: 解决办法
- 配置同步
-
- 主库创建同步用户
- 备库配置同步
- 开启slave
- 错误-3
- 错误-3：解决办法
- 验证同步
-
- 主库更新数据
- 从库检查数据
my.cnf参数前提条件
搭建一套最简单、最简易的mysql主从架构环境，至少my.cnf参数文件应具有以下参数配置：
| 参数 | 值 | 说明 |
|---|---|---|
| server_id | 1033306 | 区分每个数据库的唯一ID，可由IP+Port组成 |
| gtid_mode | on | gtid 功能需要开启 |
| enforce_gtid_consistency | on | gtid的另一个功能需要开启 |
| biglog_format | row | binlog功能需要开启 |
参数配置情况
最最简易版的参数
- 以下为主库配置文件：
[root@pg01 backups]# more /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /data/mysql/data
port = 3306
secure_file_priv= ''
log-bin = binlog
server-id = 1033306
gtid_mode = on
enforce_gtid_consistency = on
- 以下为从库配置文件：
[root@pg01 backups]# more /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /data/mysql/data
port = 3306
secure_file_priv= ''
log-bin = binlog
server-id = 1043306
gtid_mode = on
enforce_gtid_consistency = on
使用mysqldump备份
备份
[root@pg01 backups]# time mysqldump --master-data=2 --single-transaction -p -A >mysqldump_`date +%Y%m%d`.sql
Enter password:
Warning: A partial dump from a server that has GTIDs will by default include the GTIDs of all transactions, even those that changed suppressed parts of the database. If you don't want to restore GTIDs, pass --set-gtid-purged=OFF. To make a complete dump, pass --all-databases --triggers --routines --events.
real 0m2.764s
user 0m0.034s
sys 0m0.027s
参数说明
time 可显示备份过程所用时间
--master-data=2 将产生对应的binlog日志位置信息，在进行增量备份时，可从此记录的log位置之后进行备份。查看备份文件内容时将会发现以下部分的内容：
-- CHANGE MASTER TO MASTER_LOG_FILE='binlog.000005', MASTER_LOG_POS=424;
备份文件传给从库
scp mysqldump_20200318.sql 192.168.56.104:/date/mysql/backups
恢复数据
恢复数据时，命令就简单很多了
time mysql -p </data/mysql/backups/mysqldump_20200318.sql
恢复完数据后一定要登陆到数据库刷以下内存：
mysql> flush privileges ;
Query OK, 0 rows affected (0.00 sec)
报错-1
在从库上恢复数据时候，遇到了ERROR 1840
[root@pg02 backups]# time mysql -p
Enter password:
ERROR 1840 (HY000) at line 24: @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.
报错-1: 解决办法
登陆从库数据库内，重制master
[root@pg02 backups]# mysql -uroot -pmysql
mysql> reset master;
Query OK, 0 rows affected (0.02 sec)
报错-2
如果恢复完数据之后，没有执行flush privileges命令，那么此后在启动slave的时候将会获得以下报错信息：
Last_SQL_Error: Error 'Operation CREATE USER failed for 'repl'@'%'' on query. Default database: ''. Query: 'CREATE USER 'repl'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*A424E797037BF97C19A2E88CF7891C5C2038C039''
看上去说不能创建user。
报错-2: 解决办法
mysql> flush privileges ;
Query OK, 0 rows affected (0.00 sec)
配置同步
主库创建同步用户
mysql> create user 'repl'@'%' identified by 'repl';
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to 'repl'@'%' ;
Query OK, 0 rows affected (0.00 sec)
备库配置同步
change master to master_host='192.168.56.103' ,
master_port=3306 ,
master_user='repl' ,
master_password='repl' ,
master_auto_position=1;
开启slave
start slave;
查看slave 进程状态是否正常，看到是以下的内容为 正常：
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.56.103
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000005
Read_Master_Log_Pos: 1700
Relay_Log_File: pg02-relay-bin.000003
Relay_Log_Pos: 445
Relay_Master_Log_File: binlog.000005
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: 1700
Relay_Log_Space: 1495
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: 103
Master_UUID: 3a38867c-6423-11ea-9918-080027a9c49a
Master_Info_File: /data/mysql/data/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: 3a38867c-6423-11ea-9918-080027a9c49a:5-7
Executed_Gtid_Set: 3a38867c-6423-11ea-9918-080027a9c49a:1-7,
a67c95bf-f374-11ea-bc88-0800271dc433:1
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
错误-3
如果在查看状态的时候发现以下报错，无法连接到master，则说明你的服务器防火墙没有关闭
mysql> show slave status\G
Last_IO_Error: error connecting to master '[email protected]:3306' - retry-time: 60 retries: 1
错误-3：解决办法
查看防火墙状态（此为linux 6 的检查方式）
[root@pg02 backups]# service iptables status
Table: filter
Chain INPUT (policy ACCEPT)
num target prot opt source destination
1 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
2 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
3 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
5 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
num target prot opt source destination
1 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT)
num target prot opt source destination
发现防火墙为启动状态，关闭防火墙：
[root@pg02 backups]# service iptables stop
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Flushing firewall rules: [ OK ]
iptables: Unloading modules: [ OK ]
验证同步
主库更新数据
mysql> select * from dong.t1;
+------+-------+----------+------+
| id | name | city | age |
+------+-------+----------+------+
| 6 | dd | qhd | 11 |
+------+-------+----------+------+
11 rows in set (0.00 sec)
mysql> update dong.t1 set name='cbr500' where city='qhd';
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from dong.t1;
+------+--------+----------+------+
| id | name | city | age |
+------+--------+----------+------+
| 6 | cbr500 | qhd | 11 |
+------+--------+----------+------+
从库检查数据
mysql> update dong.t1 set name=‘cbr500’ where city=‘qhd’;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from dong.t1;
±-----±-------±---------±-----+
| id | name | city | age |
±-----±-------±---------±-----+
| 6 | cbr500 | qhd | 11 |
±-----±-------±---------±-----+