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这期内容当中小编将会给大家带来有关MySQL双主架构主库单点故障的解决方法，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。
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在企业中，一般系统架构的瓶颈会出现在数据库这一部分，Mysql主从架构在很大程度上解决了这部分瓶颈，但是在Mysql主从同步的架构也存在很多问题。比如：
1. 关于数据写入部分(也就是主库)往往很难做到扩展，虽然很多大公司在逻辑业务方面就进行对数据的拆分，比如商品库存按照区域去拆分(一个区域走一个库存也就是一个主库,然后定时同步总的库存)，按照商品类型去划分(一个类型的商品走一套数据库)，但是这对于很多中小型公司来说实现起来还是比较困难的；
2. 主从同步一般都是一个主库，一旦主库出现问题,就有可能直接导致整个主从同步架构崩盘，虽然发现后也是可以慢慢恢复的，但是这个恢复时间对于很多公司来说是难以接受的。
今天的这篇博文主要给解决主库单点故障这个问题提供一个思路：
一台主库(我们称之为master-01)提供服务,只负责数据的写入；
拿出一台数据库服务器(我们称之为Master-02)资源做master-01主库的从库(之间做主从同步)；
两台主库之间做高可用,可以采用keepalived等方案(一定要保证master-01同时也要作为keepalived的主)；
程序在调用主库IP地址的地方写为高可用的VIP地址；
所有提供服务的从服务器与master-02进行主从同步；
建议采用高可用策略的时候,当master-01出现问题切换到master-02的时候,即使master-01恢复了,也不要让它去自动承接VIP地址,否则可能造成数据的混写
这样做可以在一定程度上保证主库的高可用，在一台主库down掉之后,可以在极短的时间内切换到另一台主库上(尽可能减少主库宕机对业务造成的影响)，减少了主从同步给线上主库带来的压力；但是也有几个不足的地方：
master-02可能会一直处于空闲状态(其实完全可以让它承担一部分从库的角色来负责一部分查询请求的)；
这样真正提供服务的从库要等master-02先同步完了数据后才能去master-02上去同步数据，这样可能会造成一定程度的同步延迟时间的加长；
如果master-01一旦恢复正常，会不会导致数据写入混乱(这个可以在keepalived中设置响应的规则,让其不”夺权”，我们认为的去调整操作即可。
架构的简易图如下：
具体实施方案：
一、在所有需要提供服务的服务器上安装MySQL服务(建议源码安装)
1、yum安装依赖包
yum -y install cmake make gcc gcc-c++ ncurses-devel bison openssl-devel
2、添加MySQL所需要的用户/组
groupadd mysql useradd -g mysql -r mysql
3、下载MySQL源码包
wget http://dev.mysql.com/get/Downloads/MySQL-5.5/mysql-5.5.36.tar.gz
4、创建MySQL安装所需要的目录
mkdir /data/mydata/{data,tmp,logs} –pv5、解压编译安装MySQL
tar xf mysql-5.5.36.tar.gz cd mysql-5.5.36 cmake . -DCMAKE_INSTALL_PREFIX=/usr/local/mysql \ -DMYSQL_DATADIR=/data/mydata/data \ -DSYSCINFDIR=/etc \ -DWITH_INNOBASE_STORAGE_ENGINE=1 \ -DWITH_ARCHIVE_STORAGE_ENGINE=1 \ -DWITH_BLACKHOLE_STORAGE_ENGINE=1 \ -DWITH_READLINE=1 \ -DWITH_SSL=system \ -DWITH_ZLIB=system \ -DWITH_LIBWARP=0 \ -DWITH_UNIX_ADDR=/tmp/mysql.sock \ -DDEFAULT_CHARASET=uft8 \ -DDEFAULT_COLLATTON=utf9_general_ci \ make && make install
6、为MySQL提供启动脚本
cp support-files/mysql.server /etc/rc.d/init.d/mysqld
7、为master-01主库提供配置文件(32G内存较为保守(满连接占用25G左右内存)的配置文件)
[client] port = 3306 socket = /var/lib/mysql/mysql.sock default-character-set = utf-8 [mysqld] server-id = 1 port = 3306 user = mysql basedir = /usr/local/mysql datadir = /data/mydata/data tmpdir = /data/mydata/tmp socket = /var/lib/mysql/mysql.sock skip-external-locking skip-name-resolve default-storage-engine = INNODB character-set-server = utf8 wait-timeout = 100 connect_timeout = 20 interactive_timeout = 100 back_log = 300 myisam_recover event_scheduler = on log-bin=/data/mydata/logs/mysql-bin binlog_format = row max_binlog_size = 64M binlog_cache_size = 1M slave-net-timeout = 10 skip-slave-start slow_query_log = 1 long_query_time = 1 slow_query_log_file = /data/mydata/mysqllog/logs/mysql.slow log-error = /data/mydata/mysqllog/logs/error.log max_connections = 1000 max_user_connections = 1000 max_connect_errors = 10000 key_buffer_size = 32M #以MyISAM为主的服务器,要调大此值 max_allowed_packet = 64M table_cache = 4096 table_open_cache = 4096 table_definition_cache = 4096 sort_buffer_size = 512K read_buffer_size = 512K read_rnd_buffer_size = 512K join_buffer_size = 512K tmp_table_size = 64M max_heap_table_size = 64M query_cache_type = 0 query_cache_size = 0 bulk_insert_buffer_size = 16M thread_cache_size = 64 thread_concurrency = 16 #CPU核数*2 thread_stack = 256K innodb_data_home_dir = /data/mydata/data innodb_log_group_home_dir = /data/mydata/mysqllog/logs innodb_data_file_path = ibdata1:1G:autoextend innodb_buffer_pool_size = 16G innodb_buffer_pool_instances = 4 innodb_additional_mem_pool_size = 16M innodb_log_file_size = 512M innodb_log_buffer_size = 32M innodb_log_files_in_group = 3 innodb_flush_log_at_trx_commit = 2 innodb_lock_wait_timeout = 10 innodb_sync_spin_loops = 40 innodb_max_dirty_pages_pct = 90 innodb_support_xa = 1 innodb_thread_concurrency = 0 innodb_thread_sleep_delay = 500 innodb_file_io_threads = 4 innodb_concurrency_tickets = 1000 log_bin_trust_function_creators = 1 innodb_flush_method = O_DIRECT innodb_file_per_table #是否采用单表单空间 innodb_write_io_threads = 8 innodb_read_io_threads = 8 innodb_io_capacity = 1000 innodb_file_format = Barracuda #不开启单表单空间,此选项无效 innodb_purge_threads = 1 innodb_purge_batch_size = 32 innodb_old_blocks_pct = 75 innodb_change_buffering = all transaction_isolation = READ-COMMITTED [mysqldump] quick max_allowed_packet = 32M [mysql] no-auto-rehash [myisamchk] key_buffer_size = 64M sort_buffer_size = 256M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 10240
8、为master-02提供配置文件
master-02的配置文件仅需在master-01上稍作修改 server-id = 20 log_slave_updates = 1 #添加(将复制事件写入binlog,一台服务器既做主库又做从库此选项必须要开启) replicate-same-server-id=0 #添加(防止MySQL循环更新) relay_log_recovery = 1 #添加(MySQLrelay_log的自动修复功能)
9、为从库提供配置文件(8G)
[client] port = 3306 socket = /var/lib/mysql/mysql.sock default-character-set = utf8 [mysqld] server-id = 2 port = 3306 user = mysql basedir = /usr/local/mysql datadir = /data/mydata/data tmpdir = /data/mydata/tmp socket = /var/lib/mysql/mysql.sock skip-external-locking skip-name-resolve default-storage-engine = INNODB character-set-server = utf8 wait-timeout = 100 connect_timeout = 20 interactive_timeout = 100 back_log = 300 myisam_recover event_scheduler = on log-bin=/data/mydata/logs/mysql-bin binlog_format = row max_binlog_size = 64M binlog_cache_size = 1M slave-net-timeout = 10 relay_log_recovery = 1 slow_query_log = 1 long_query_time = 1 slow_query_log_file = /data/mydata/mysqllog/logs/mysql.slow log-error = /data/mydata/mysqllog/logs/error.log max_connections = 500 max_user_connections = 500 max_connect_errors = 10000 key_buffer_size = 32M #以MyISAM为主的服务器,要调大此值 max_allowed_packet = 64M table_cache = 2048 table_open_cache = 2048 table_definition_cache = 2048 sort_buffer_size = 128K read_buffer_size = 128K read_rnd_buffer_size = 128K join_buffer_size = 128K tmp_table_size = 16M max_heap_table_size = 16M query_cache_type = 0 query_cache_size = 0 bulk_insert_buffer_size = 16M thread_cache_size = 64 thread_concurrency = 4 #CPU核数*2 thread_stack = 128K innodb_data_home_dir = /data/mydata/data innodb_log_group_home_dir = /data/mydata/mysqllog/logs innodb_data_file_path = ibdata1:1G:autoextend innodb_buffer_pool_size = 2G innodb_buffer_pool_instances = 4 innodb_additional_mem_pool_size = 4M innodb_log_file_size = 512M innodb_log_buffer_size = 16M innodb_log_files_in_group = 3 innodb_flush_log_at_trx_commit = 2 innodb_lock_wait_timeout = 10 innodb_sync_spin_loops = 40 innodb_max_dirty_pages_pct = 90 innodb_support_xa = 1 innodb_thread_concurrency = 0 innodb_thread_sleep_delay = 500 innodb_file_io_threads = 4 innodb_concurrency_tickets = 1000 log_bin_trust_function_creators = 1 innodb_flush_method = O_DIRECT innodb_file_per_table #是否采用单表单空间 innodb_write_io_threads = 8 innodb_read_io_threads = 8 innodb_io_capacity = 1000 innodb_file_format = Barracuda #不开启单表单空间,此选项无效 innodb_purge_threads = 1 innodb_purge_batch_size = 32 innodb_old_blocks_pct = 75 innodb_change_buffering = all transaction_isolation = READ-COMMITTED [mysqldump] quick max_allowed_packet = 32M [mysql] no-auto-rehash [myisamchk] key_buffer_size = 64M sort_buffer_size = 256M read_buffer = 2M write_buffer = 2M [mysqlhotcopy] interactive-timeout [mysqld_safe] open-files-limit = 10240
10、初始化MySQL
/usr/local/mysql/scripts/mysql_install_db --user=mysql --datadir=/data/mydata/data/ --basedir=/usr/local/mysql
11、为启动脚本赋予可执行权限并启动MySQL
chmod +x /etc/rc.d/init.d/mysqld /etc/init.d/mysqld start
二、 配置master-01
1、添加主从同步账户
mysql> grant replication slave on *.* to 'repl'@'192.168.237.%' idetified by '123456'; mysql> flush privileges;
2、查看主库的状态
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000009 | 652 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.01 sec)
3、因为这是测试环境,可以保证没数据写入,否则需要先锁表-->查看状态-->备份数据-->查看状态(保证没变)-->解锁表
三、 配置master-02
1、配置master-02为master-01的从
#若是线上有数据需要先导入数据 mysql> CHANGE MASTER TO -> MASTER_HOST='192.168.237.128', -> MASTER_PORT=3306, -> MASTER_USER='repl', -> MASTER_PASSWORD='123456', -> MASTER_LOG_FILE='mysql-bin.000009', -> MASTER_LOG_POS=652; Query OK, 0 rows affected (0.03 sec) mysql> start slave; mysql> show slave status \G Slave_IO_Running: Yes #确保为yes Slave_SQL_Running: Yes #确保为yes
2、配置master-02的同步用户
mysql> grant replication slave on *.* to 'repl’@’192.168.237.%' identified by '123456'; mysql> flush privileges;
3、查看master-02的状态
mysql> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000004 | 689 | | | +------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
四、从库根据上面步骤配置为master-02的从即可(为了节省篇幅不再一一赘述)
五、在master-01上创建一个数据库测试同步效果
六、去master-02跟从库上分别查看是否已经同步过数据来
好了，至此数据同步已经完成。
上述就是小编为大家分享的MySQL双主架构主库单点故障的解决方法了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注创新互联行业资讯频道。
