mysql主从复制配置
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同步原理:
- 同步时从库由两个线程完成(IO,SQL),主库由一个线程完成(IO);
- 要把主库的数据先还原到从库,主库备份的点就是从库change master的点,或者使用参数--master-data=1
- 要在从库上配置连接主库的IP,用户名,账号,密码,文件名,位置,及pos点
- 在开启开关之前,在某一个时间点,主库和从库数据一致
- 要在主库建立专门用于从库同步的账号
- 主库要打开bin-log开关,否则没法同步
- 从库打开开关的过程(两个线程工作的过程)
配置过程:
- 准备两台数据环境,或者单台多实例环境,能否正常启动和登陆。
- 配置my.cnf文件,主库配置log-bin和server-id参数,从库配置server-id参数,不能和主库及其他从库一样,一般不开启从库bin-log,注意,配置参数后要重启生效。
- 登陆主库增加用于从库连接主库同步的账户,例如rep,并授权replication slave同步权限。
- 登陆主库,整库锁表,flush table with read lock(窗口关闭后即失效,超时参数到了也失效);然后show master status 查看binlog的位置状态
- 新开窗口,linux命令行备份或导出原有的数据库数据,并拷贝到从库所在的服务器目录。
- 如果数据量很大,并且允许停机,可以停机打包,而不用mysqldump。
- 解锁主库,unlock tables;
- 把主库导出的原有数据恢复到从库
- 根据主库的show master status查看binlog的位置状态,再从库执行change master to...语句
- 从库开启同步开关,start slave。
配置:
master 3307
slave 3308
==================================================主库============================================
1. 开启bin-log,保证主备库的server-id不相同
2. bin-log要放在[mysqld]模块下面
3. 检查主库的server_id
[[email protected] ~]# mysql -uroot -proot -S /data/3307/mysql.sock -e "show variables like ‘server_id‘"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | server_id | 1 | +---------------+-------+
4. 检查主库是否开启log_bin,如果没有开启,修改my.cnf文件进行添加:
[[email protected] ~]# mysql -uroot -proot -S /data/3307/mysql.sock -e "show variables like ‘log_bin%‘"; +---------------------------------+---------------------------------+ | Variable_name | Value | +---------------------------------+---------------------------------+ | log_bin | ON | | log_bin_basename | /data/3307/data/mysql-bin | | log_bin_index | /data/3307/data/mysql-bin.index | | log_bin_trust_function_creators | OFF | | log_bin_use_v1_row_events | OFF | +---------------------------------+---------------------------------+
5. 连接到主库,创建用户,可以从备库登陆过来进行日志读取:
[[email protected] ~]# mysql -uroot -proot -S /data/3307/mysql.sock
mysql> grant replication slave on *.* to ‘rep‘@‘192.168.56.99‘ identified by ‘abbott‘; Query OK, 0 rows affected, 1 warning (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec)
6. 锁定主库的表,然后进行备份,否则备份集将不成功
mysql> flush table with read lock; Query OK, 0 rows affected (0.00 sec)
7. 查看此时的position,确保备份完成之后不会改变
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000003 | 600 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
8. 查看log
mysql> show master logs; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 727 | | mysql-bin.000002 | 833 | | mysql-bin.000003 | 600 | +------------------+-----------+ 3 rows in set (0.00 sec)
9. 对主库进行备份
[[email protected] log]# mysqldump -uroot -proot -S /data/3307/mysql.sock -A -B --events --master-data=2 > /opt/rep.sql
[[email protected] opt]# mysqldump -uroot -proot -S /data/3307/mysql.sock -A -B --master-data=1 --single-transaction >/opt/full.sql
企业推荐:不停库(使用这种方式,不需要指定binlog位置,也不需要锁表,--single-transaction参数可以屏蔽其余会话的增删改,即不需要加master_log_file和master_log_pos这两个参数)
10. 检查备份后position是否改变
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000003 | 600 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
11. 如果检查没有问题,那么就取消锁定
mysql> unlock tables; Query OK, 0 rows affected (0.00 sec)
+++++++++++++++++++++++++++++++++++++++++++++++++++备库++++++++++++++++++++++++++++++++++++++++++++++++++++
12. 在备库恢复备份的文件
[[email protected] opt]# mysql -uroot -proot -S /data/3308/mysql.sock </opt/rep.sql
13. 查看备份是否恢复成功
[[email protected] opt]# mysql -uroot -proot -S /data/3308/mysql.sock mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | ZX | | abbott | | mysql | | performance_schema | | sys | +--------------------+ 6 rows in set (0.00 sec)
14. 指定备库同步主库的信息
change master to MASTER_HOST=‘192.168.56.99‘, MASTER_PORT=3307, MASTER_USER=‘rep‘, MASTER_PASSWORD=‘abbott‘, MASTER_LOG_FILE=‘mysql-bin.000003‘, MASTER_LOG_POS=600; Query OK, 0 rows affected, 2 warnings (0.13 sec)
15. 查看master_info里记录的信息是否和指定同步的位置一样
[[email protected] data]# cat master.info 24 mysql-bin.000003 600 192.168.56.99 rep abbott 3307
16. 备库开始进行同步
mysql> start slave; Query OK, 0 rows affected (0.01 sec)
17. 查看同步情况,其中参数Slave_IO_Running和Slave_SQL_Running都是yes。
mysql> show slave status\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.56.99 Master_User: rep Master_Port: 3307 Connect_Retry: 60 Master_Log_File: mysql-bin.000003 Read_Master_Log_Pos: 600 Relay_Log_File: MySQL-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: 600 Relay_Log_Space: 527 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: 1 Master_UUID: 3b9f6e49-5a6b-11e7-b603-08002714955b Master_Info_File: /data/3308/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: Executed_Gtid_Set: Auto_Position: 0 Replicate_Rewrite_DB: Channel_Name: 1 row in set (0.00 sec)
18. 测试,在主库创建一个库abc,可以看到在备库已经同步过来。
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | ZX | | abbott | | abc | | mysql | | performance_schema | | sys | +--------------------+ 7 rows in set (0.00 sec)
查看线程状态:
主库:
mysql> show processlist; +----+------+---------------------+--------+-------------+------+---------------------------------------------------------------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+------+---------------------+--------+-------------+------+---------------------------------------------------------------+------------------+ | 9 | rep | 192.168.56.99:38359 | NULL | Binlog Dump | 215 | Master has sent all binlog to slave; waiting for more updates | NULL | | 10 | root | localhost | abbott | Query | 0 | starting | show processlist | +----+------+---------------------+--------+-------------+------+---------------------------------------------------------------+------------------+ 2 rows in set (0.00 sec)
备库:
mysql> show processlist; +----+-------------+-----------+--------+---------+------+--------------------------------------------------------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+-------------+-----------+--------+---------+------+--------------------------------------------------------+------------------+ | 15 | root | localhost | abbott | Query | 0 | starting | show processlist | | 16 | system user | | NULL | Connect | 237 | Waiting for master to send event | NULL | | 17 | system user | | NULL | Connect | 144 | Slave has read all relay log; waiting for more updates | NULL | +----+-------------+-----------+--------+---------+------+--------------------------------------------------------+------------------+ 3 rows in set (0.00 sec)
要点:
- 异步方式同步;
- 逻辑同步模式,多种模式,默认是通过SQL语句执行;
- 主库通过记录binlog实现对从库的同步,binlog记录数据库的更新语句;
- 主库1个IO线程,从库由1个IO线程和一个SQL线程来完成;
- 从库关键文件master.info,relay-log,relay-info功能;
- 如果从库还想级联从库,需要打开log-bin参数和log-slave-updates参数。
生产场景快速配置mysql主从复制方案
- 安装好要配置从库的数据库,配置好log-bin和server-id参数
- 无需配置主库my.cnf文件,主库的log-bin和server-id参数默认就是配置好的
- 登录主库增加用于从库连接主库同步的账户 例如:rep 并授权replication slave同步的权限
- 使用mysqldump带--master-data=1 备份的全备数据恢复到从库
- mysqldump -uroot -proot -S /data3307/mysql.sock -A -B --master-data=1 --single-transaction > /opt/full.sql
- 在从库执行change master to ..语句 无需binlog文件及对应位置点
- 从库开启同步开关,start slave
- 从库show slave status\G 检查同步状态,并在主库进行更新测试
mysql其他主从复制实现:
- NFS网络文件共享
- samba共享数据 http://taokey.blog.51cto.com/4633273/1203553
- 定时任务或守护进程结合rsync scp
- inotify+rsync触发式实时数据同步
- ftp数据同步
- ssh key+scp/rsync
主服务器挂了,人工或自动切换到从服务器:http://oldboy.blog.51cto.com/2561410/1240412
可以保证同步的方式:
- 主库挂了,把主库的bin-log拿过来应用;
- 双写;
- 通过应用程序写一分钟的日志;
- 把异步同步换成实时同步(即半同步);
读写分离:
- 中大型公司,通过程序(php,java)
- 测试环境:代理软件(mysql-proxy,Amoeba)
- 门户网站:分布式dbproxy(读写分离,hash负载均衡,健康检查)
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