传统上：一个主可以有多从，但是一个从服务器只有一个主
而 今：一从多主
PS:服务器版本需要保持一致：如果不一致，从服务器版本必须高于主服务器！当然，最好版本相同
简单配置过程：
一．master
1，启用二进制日志
1， 设置一个在当前集群中唯一的server-id
2， 创建一个有复制权限的账号（REPLICATIONSLAVE ,REPLICATION CLIENT）
二．slave
1， 启用中继日志
2， 设置一个在当前集群中唯一的server-id
3， 使用有复制权限用户账号连接至主服务器，并启动复制线程
插播：备份
Mysqldunmp 实现备份是，由于本身对有些存储引荇的备份，如myisa只能从温备，innodb能够热备，备份需要启动一个大事务
Lvm快照，几乎热备，事先请求锁定数据库，创建快照，释放锁。工具perl脚本借助快照备份
Xtrabckup：单表导入导出，流式化传输备份，物理备份工具。真正使用需要考虑备份策略，如：全备加增量备份，全备加差异备份，xtrabackup本身支持增量，但是增量只会innodb备份，myisa是不支持的。默认mysql启用最好启用innodb
rmp包：mariadb-5.5.40-linux-x86_64.tar.gz一，主从复制mkdir -pv /mydata/datagroupadd -r -g 306 mysqluseradd -r -g 306 -u 306 mysqlchown -R mysql.mysql /mydatatar xf mariadb-5.5.40-linux-x86_64.tar.gz -C /usr/localcd /usr/localln -sv mariadb-5.5.40-linux-x86_64 mysqlcd mysql/chown -R root.mysql ./*scripts/mysql_install_db --user=mysql --datadir=/mydata/datamkdir /etc/mysqlcp support-files/my-large.cnf /etc/mysql/my.cnfvim /etc/mysql/my.cnfdatadir=/mydata/datainnodb_file_per_table = onskip_name_resolve = oncp support-files/mysql.server /etc/init.d/mysqldchkconfig --add mysqldservice mysqld startmaster配置：vim /etc/mysql/my.cnflog-bin=master-bin 线上机器不能修改server-id = 1master主机授权slave复制/usr/local/mysql/bin/mysqlMariaDB [(none)]> GRANT REPLICATION CLIENT,REPLICATION SLAVE ON *.* TO 'repluser'@'192.168.%.%' IDENTIFIED BY 'replpass';MariaDB [(none)]> FLUSH PRIVILEGES;slave配置：
vim /etc/mysql/my.cnfserver-id = 20relay-log = relay-bin 中继日志read-only = on master查看MariaDB [(none)]> SHOW GLOBAL VARIABLES LIKE '%only';+---------------+-------+| Variable_name | Value |+---------------+-------+| read_only | OFF |+---------------+-------+1 row in set (0.00 sec)+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++read_only 是不能阻止所有人向里面写入数据的，只能组织普通账号++组织所有人不能写的话，在配置文件中添加如下：+read-only = on +service mysqld restart++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++在配置之前查看下master的日志MariaDB [(none)]> SHOW MASTER STATUS;+-------------------+----------+--------------+------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |+-------------------+----------+--------------+------------------+| master-bin.000002 | 497 | | |+-------------------+----------+--------------+------------------++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++因为是第一次复制，主从都是空的，指明从当前这一刻开始复制+如果新加入的从服务器，而主服务器已经工作很久，这时候应备份主服务器的数据恢复到从服务器，在从备份的的位置向后复制++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++slave：MariaDB [(none)]> CHANGE MASTER TO MASTER_HOST='192.168.131.139',MASTER_USER='repluser',MASTER_PASSWORD='replpass',MASTER_LOG_FILE='master-bin.000002',MASTER_LOG_POS=497,MASTER_CONNECT_RETRY=5,MASTER_HEARTBEAT_PERIOD=2;Query OK, 0 rows affected (0.14 sec)+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++CHANGE MASTER TO +MASTER_HOST='192.168.131.139', MASTER主机ip+MASTER_USER='repluser', 复制权限的用户+MASTER_PASSWORD='replpass', 复制权限的用户的密码+MASTER_LOG_FILE='master-bin.000001', 日志文件开始位置+MASTER_LOG_POS=497, 日志文件数值（在master 数据库中使用SHOW MASTER STATUS;查看当前是多少便从多少开始！！如果新加入的从服务器，而主服务器已经工作很久，这时候应备份主服务器的数据恢复到从服务器，在从备份的的位置向后复制）+MASTER_CONNECT_RETRY=5, 5秒钟复制一次+MASTER_HEARTBEAT_PERIOD=2; 心跳信息时间间隔++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++完成后检测MariaDB [(none)]> SHOW SLAVE STATUSG*************************** 1. row *************************** Slave_IO_State: Master_Host: 192.168.131.139 Master_User: repluser Master_Port: 3306 Connect_Retry: 5 Master_Log_File: master-bin.000001 Read_Master_Log_Pos: 497 Relay_Log_File: relay-bin.000001 已经开始 Relay_Log_Pos: 4 Relay_Master_Log_File: master-bin.000001 Slave_IO_Running: No 从服务器io线程 Slave_SQL_Running: No 从服务器sql线程 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: 497 Relay_Log_Space: 245 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: NULLMaster_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: 01 row in set (0.00 sec)启动slave io线程和sql线程MariaDB [(none)]> START SLAVE; Query OK, 0 rows affected (0.00 sec而后查看slave的relay-bin.000001和relay-log.info已经存在[root@mysql-slave ~]# ll /mydata/data/ -rw-rw---- 1 mysql mysql 245 Jul 4 23:26 relay-bin.000001-rw-rw---- 1 mysql mysql 19 Jul 4 23:26 relay-bin.index-rw-rw---- 1 mysql mysql 43 Jul 4 23:26 relay-log.infodrwx------ 2 mysql root 4096 Jul 4 22:09 test[root@mysql-slave ~]# master端：MariaDB [(none)]> SHOW MASTER STATUSG*************************** 1. row *************************** File: master-bin.000002 Position: 677 Binlog_Do_DB: Binlog_Ignore_DB: 1 row in set (0.00 sec)MariaDB [(none)]> slave端：MariaDB [(none)]> SHOW SLAVE STATUSG;*************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.131.139 Master_User: repluser Master_Port: 3306 Connect_Retry: 5 Master_Log_File: master-bin.000002 Read_Master_Log_Pos: 776 Relay_Log_File: localhost-relay-bin.000002 Relay_Log_Pos: 809 Relay_Master_Log_File: master-bin.000002 Slave_IO_Running: Yes Slave_SQL_Running: YesPS：在做mysql主从时，中间最好不要修改主机名。否则可能会出现Slave_IO_Running和Slave_SQL_Running起不来的情况！MASTER：MariaDB [(none)]> CREATE DATABASE markdb;Query OK, 1 row affected (0.00 sec)MariaDB [(none)]> use markdbDatabase changedMariaDB [markdb]> create table tn1 (id int);Query OK, 0 rows affected (0.05 sec)SLAVE：MariaDB [(none)]> use markdbDatabase changedMariaDB [markdb]> show tables;+------------------+| Tables_in_markdb |+------------------+| tn1 |+------------------+1 row in set (0.06 sec)帮助选项MariaDB [markdb]> HELP CHANGE MASTER TOoption: MASTER_BIND = 'interface_name' | MASTER_HOST = 'host_name' 主服务器地址 | MASTER_USER = 'user_name' 有复制权限的用户名 | MASTER_PASSWORD = 'password' 用户密码 | MASTER_PORT = port_num 主服务器端口 | MASTER_CONNECT_RETRY = interval 链接重试的时间间隔 | MASTER_HEARTBEAT_PERIOD = interval 心跳检测的时间间隔 | MASTER_LOG_FILE = 'master_log_name' 主服务器二进制日志文件 | MASTER_LOG_POS = master_log_pos 二进制日志文件中的位置 | RELAY_LOG_FILE = 'relay_log_name' | RELAY_LOG_POS = relay_log_pos 基于ssl复制使用的 | MASTER_SSL = {0|1} | MASTER_SSL_CA = 'ca_file_name' | MASTER_SSL_CAPATH = 'ca_directory_name' | MASTER_SSL_CERT = 'cert_file_name' | MASTER_SSL_KEY = 'key_file_name' | MASTER_SSL_CIPHER = 'cipher_list' | MASTER_SSL_VERIFY_SERVER_CERT = {0|1} | IGNORE_SERVER_IDS = (server_id_list) 做环装复制时。mysql环境变量：export PATH=/usr/local/mysql/bin:$PATH
