MySQL主主复制

       MySQL主主复制结构区别于主从复制结构。在主主复制结构中，两台服务器的任何一台上面的数据库存发生了改变都会同步到另一台服务器上，这样两台服务器互为主从，并且都能向外提供服务。

一、搭建环境描述：

主机A IP：192.168.1.201

主机B IP：192.168.1.202

操作系统：centos6.5-x86

Mysql版本：mysql-5.7.12-linux-glibc2.5-x86_64.tar.gz

安装所需依赖包：yum install  libaio-devel   –y

关闭SElinux及IPtables。

二、配置主主复制：

1、修改配置文件

vim /etc/my.cnf

[mysqld] ########basic settings######## server- id = 1 #另一台ID不同 port = 3306 user = mysql bind_address = 192.168.1.201 #另一台IP不用 autocommit = 0 character_set_server=utf8mb4 skip_name_resolve = 1 max_connections = 800 max_connect_errors = 1000 datadir = /usr/local/mysql/data transaction_isolation = READ-COMMITTED explicit_defaults_for_timestamp = 1 join_buffer_size = 134217728 tmp_table_size = 67108864 tmpdir = /tmp max_allowed_packet = 16777216 sql_mode = "STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION,NO_ZERO_DATE,NO_ZERO_IN_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER" interactive_timeout = 1800 wait_timeout = 1800 read_buffer_size = 16777216 read_rnd_buffer_size = 33554432 sort_buffer_size = 33554432 ########log settings######## log_error = error.log slow_query_log = 1 slow_query_log_file = slow.log log_queries_not_using_indexes = 1 log_slow_admin_statements = 1 log_slow_slave_statements = 1 log_throttle_queries_not_using_indexes = 10 expire_logs_days = 90 long_query_time = 2 min_examined_row_limit = 100 ########replication settings######## master_info_repository = TABLE relay_log_info_repository = TABLE log_bin = bin.log sync_binlog = 1 gtid_mode = on enforce_gtid_consistency = 1 log_slave_updates binlog_format = row relay_log = relay.log relay_log_recovery = 1 binlog_gtid_simple_recovery = 1 slave_skip_errors = all # slave slave-parallel- type = LOGICAL_CLOCK slave-parallel-workers = 0 #slave-parallel-workers = 16 ########innodb settings######## innodb_buffer_pool_size = 750M // 内存的75%比较合适 innodb_buffer_pool_instances = 16 innodb_buffer_pool_load_at_startup = 1 innodb_buffer_pool_dump_at_shutdown = 1 innodb_lru_scan_depth = 2000 innodb_lock_wait_timeout = 10000 innodb_io_capacity = 4000 innodb_io_capacity_max = 8000 innodb_flush_method = O_DIRECT innodb_flush_neighbors = 1 innodb_log_file_size = 4G innodb_log_buffer_size = 16777216 innodb_purge_threads = 4 innodb_large_prefix = 1 innodb_thread_concurrency = 64 innodb_print_all_deadlocks = 1 innodb_strict_mode = 1 innodb_sort_buffer_size = 67108864 innodb_flush_log_at_trx_commit = 2 innodb_read_io_threads = 16 innodb_write_io_threads = 16 ########semi sync replication settings######## plugin_dir= /usr/local/mysql/lib/plugin plugin_load = "rpl_semi_sync_master=semisync_master.so;rpl_semi_sync_slave=semisync_slave.so" loose_rpl_semi_sync_master_enabled = 1 loose_rpl_semi_sync_slave_enabled = 1 loose_rpl_semi_sync_master_timeout = 5000 [mysqld-5.7] innodb_buffer_pool_dump_pct = 40 innodb_page_cleaners = 4 innodb_undo_log_truncate = 1 innodb_max_undo_log_size = 2G innodb_purge_rseg_truncate_frequency = 128 binlog_gtid_simple_recovery=1 log_timestamps=system transaction_write_set_extraction=MURMUR32 show_compatibility_56=on

2、初始化mysql数据库

/usr/local/mysql/bin/mysqld --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --initialize
/etc/init.d/mysqld start

3、设置密码

mysql5.7不允许密码为空了，所以必须得设置密码




grep "temporary password" /usr/local/mysql/data/error.log

2016-07-04T09:50:17.455227+08:00 1 [Note] A temporary password is generated  for  root@localhost: wLEM;g+?&1eF
/usr/local/mysql/bin/mysql  -uroot -p
#输入日志里的密码
mysql> alter user  'root' @ 'localhost'  identified by  '123456' ;
mysql> flush privileges;

4、配置数据同步

#两台Mysql同时添加同步用户

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mysql> create user 'repl' @ '192.168.1.%' identified by '123456' ; mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl' @ '192.168.1.%' ; mysql> flush privileges;

锁一下表，追平两台机器数据，然后解锁。

先看看GTID是否打开

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mysql> show global variables like '%gtid%' ; +--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | enforce_gtid_consistency | ON | | gtid_executed | | | gtid_mode | ON | | gtid_owned | | | gtid_purged | | +--------------------------+-------+ 5 rows in set (0.10 sec)

#说明gtid功能已启动。

GTID同步数据不用再记录对方的log文件和位置了，用master_auto_position=1就行，不过你用老的方法查看master的logfile和logpos，同步也是可以的。

#在两台Mysql上都运行，IP得互指

mysql> change master to master_host='192.168.1.201', master_user='repl',master_password='123456',master_auto_position=1; 

mysql> start slave;

show slave status\G ;

#表示同步的文件和位置

     Master_Log_File:

          Read_Master_Log_Pos: 4

#显示下面表示工作正常

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

#表示当前同步的数据库

Replicate_Do_DB: nzabbix,szabbix

过程中可能遇到的错误及解决方法：

错误一：

mysql>  start slave;

ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository

解决方法：

mysql> reset slave;

错误二：

Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it).

解决方法：

修改my.cnf配置文件中，slave_skip_errors = all