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
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2、初始化mysql数据库
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/usr/local/mysql/bin/mysqld
--user=mysql --basedir=
/usr/local/mysql
--datadir=
/usr/local/mysql/data
--initialize
/etc/init
.d
/mysqld
start
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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;
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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
