Percona XtraBackup工具提供了一种在系统运行时执行MySQL数据热备份的方法。
Percona XtraBackup在事务系统上执行联机非阻塞，紧密压缩，高度安全的完整备份，因此在计划的维护时段内，应用程序仍保持完全可用。
环境准备：
master:192.168.0.106:3306
slave:192.168.0.105:3306
datadir: /data/mysql/mysql3306/data
cnfpath: /data/mysql/mysql3306/my3306.cnf
XtraBackup 安装，两台机器都安装：
下载地址：https://www.percona.com/downloads/Percona-XtraBackup-LATEST/
TheMaster$ wget https://www.percona.com/downloads/Percona-XtraBackup-LATEST/Percona-XtraBackup-8.0-7/binary/redhat/7/x86_64/percona-xtrabackup-80-8.0.7-1.el7.x86_64.rpm
TheMaster$ yum install -y percona-xtrabackup-80-8.0.7-1.el7.x86_64.rpm
1、在Master制作一个备份
TheMaster$ mkdir xtrabackup_backupfiles
TheMaster$ xtrabackup --defaults-file=/data/mysql/mysql3306/my3306.cnf -S /tmp/mysql3306.sock -uroot -p‘‘ --backup --target-dir=./xtrabackup_backupfiles
...
completed OK!
为了让快照是一致的:需要prepare备份数据：
TheMaster$ xtrabackup -S /tmp/mysql3306.sock -uroot -p --prepare --target-dir=./xtrabackup_backupfiles/
...
completed OK!
undo log目录需要处理下，默认会解压到xtrabackup_backupfiles目录下，在my3306.cnf中定义在/data/mysql/mysql3306/data/undolog/下，所以：
TheMaster$ cd xtrabackup_backupfiles && mkdir undolog && mv undo_* undolog/
2、复制备份数据到Slave上
使用rsync或scp将数据从Master复制到Slave。如果直接将数据同步到slave的数据目录，建议在这之前先停止mysqld。
TheMaster$ rsync -avpP -e ssh ./xtrabackup_backupfiles/ 192.168.0.105:/data/mysql/mysql3306/data/
复制数据前，您可以备份原始或先前安装的MySQL datadir（注意：在移动mysqld的内容或将快照移动到其datadir之前，请确保mysqld已关闭。）：
TheSlave$ mv /data/mysql/mysql3306/data /data/mysql/mysql3306/data_bak
复制数据后，确保MySQL有权限访问
TheSlave$ chown -R mysql:mysql /data/mysql/mysql3306/data
3、创建Master上配置复制账号
TheMaster|mysql> GRANT REPLICATION SLAVE ON *.* TO ‘repl‘@‘192.168.0.%‘ IDENTIFIED BY ‘repl‘;
测试连接
TheSlave$ mysql --host=192.168.0.106 --user=repl --password=repl
mysql> SHOW GRANTS;
4、配置Slave上的MySQL服务器
首先将my3306.cnf从TheMaster复制到TheSlave：
TheSlave$ scp root@192.168.0.106:/data/mysql/mysql3306/my3306.cnf /data/mysql/mysql3306/
TheSlave$ chown -R mysql:mysql /data/mysql/mysql3306/data/my3306.cnf
修改TheSlave上的my3306.cnf：
server-id=1053306 # 建议ip最后一位+端口号
启动TheSlave 上的 mysqld
TheSlave$ /usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf &
观察error.log是否有错误
TheSlave$ more /data/mysql/mysql3306/data/error.log
5、启动复制
TheSlave$ cat /data/mysql/mysql3306/data/xtrabackup_binlog_info mysql-bin.000012 195 e8f74dde-ed8e-11e9-8ebb-000c29f5c092:1-3
执行CHANGE MASTER语句在MySQL命令行：
TheSlave|mysql> CHANGE MASTER TO MASTER_HOST=‘192.168.0.106‘, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘repl‘, MASTER_AUTO_POSITION=1;
开始复制：
TheSlave|mysql> START SLAVE;
6、检查
TheSlave|mysql> SHOW SLAVE STATUS \G ... Slave_IO_Running: Yes Slave_SQL_Running: Yes ... Seconds_Behind_Master: 0 ...
看到IO和SQL线程处于运行中 （Yes）表示复制正常。
root@localhost 22:42:41 [(none)]> show slave status\G ERROR 2006 (HY000): MySQL server has gone away No connection. Trying to reconnect... Connection id: 16 Current database: *** NONE *** *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.0.106 Master_User: repl Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000016 Read_Master_Log_Pos: 383 Relay_Log_File: localhost-relay-bin.000002 Relay_Log_Pos: 557 Relay_Master_Log_File: mysql-bin.000016 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: 383 Relay_Log_Space: 769 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: 1063306 Master_UUID: e8f74dde-ed8e-11e9-8ebb-000c29f5c092 Master_Info_File: mysql.slave_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: e8f74dde-ed8e-11e9-8ebb-000c29f5c092:4 Executed_Gtid_Set: e8f74dde-ed8e-11e9-8ebb-000c29f5c092:1-4 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: Master_public_key_path: Get_master_public_key: 0 Network_Namespace: 1 row in set (0.00 sec)