MySQL备份与恢复之热拷贝（4）_Mysql

在上一篇文章中我们提到热备，热备也就是在MySQL或者其他数据库服务在运行的情况下进行备份。本文分享另外一种备份的方法，也就是热拷贝。热拷贝跟热备很类似，只不过热备使用mysqldump命令，热拷贝使用mysqlhotcopy命令。热拷贝的优势在于支持服务运行中进行备份，速度快，性能好；劣势在于只能备份MyIsam的表，无法备份InnoDB的表。所以在生产环境中应该酌情使用。

示意图

MySQL备份与恢复之热拷贝（4）

热备模拟

第一步，热拷贝

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									[root@serv01 databackup]# mysqlhotcopy -uroot -p123456 --database larrydb > larrydb_hostcopy.sql

									Can't locate DBI.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at /usr/local/mysql/bin/mysqlhotcopy line 25.

									BEGIN failed--compilation aborted at /usr/local/mysql/bin/mysqlhotcopy line 25.

第二步，报错。因为这个命令是用perl写的或者此命令需要perl支持，所以需要安装perl

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									[root@serv01 databackup]# yum install perl* -y

第三步，对数据库larrydb热拷贝

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									[root@serv01 databackup]# mysqlhotcopy --help

#第一种写法

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									[root@serv01 databackup]# mysqlhotcopy --user=root --password=123456 larrydb /databackup/

#第二种写法

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									[root@serv01 databackup]# mysqlhotcopy -u root -p 123456 larrydb /databackup/

									Flushed 2 tables with read lock (`larrydb`.`class`, `larrydb`.`stu`) in 0 seconds.

									Locked 0 views () in 0 seconds.

									Copying 5 files...

									Copying indices for 0 files...

									Unlocked tables.

									mysqlhotcopy copied 2 tables (5 files) in 0 seconds (0 seconds overall).

第四步，模拟数据丢失

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									[root@serv01 databackup]# ll larrydb

									total 36

									-rw-rw----. 1 mysql mysql 8590 Sep 10 19:07 class.frm

									-rw-rw----. 1 mysql mysql  65 Sep 10 19:07 db.opt

									-rw-rw----. 1 mysql mysql 8618 Sep 10 19:07 stu.frm

									-rw-rw----. 1 mysql mysql  48 Sep 10 19:07 stu.MYD

									-rw-rw----. 1 mysql mysql 1024 Sep 10 19:07 stu.MYI

									mysql> use larrydb;

									Database changed

									mysql> show tables;

									+-------------------+

									| Tables_in_larrydb |

									+-------------------+

									| class       |

									| stu        |

									+-------------------+

									2 rows in set (0.00 sec)

									mysql> show create table class \G;

									*************************** 1. row ***************************

									    Table: class

									Create Table: CREATE TABLE `class` (

									 `cid` int(11) DEFAULT NULL,

									 `cname` varchar(30) DEFAULT NULL

									) ENGINE=InnoDB DEFAULT CHARSET=latin1

									1 row in set (0.00 sec)

									ERROR: 

									No query specified

									mysql> show create table stu \G;

									*************************** 1. row ***************************

									    Table: stu

									Create Table: CREATE TABLE `stu` (

									 `sid` int(11) DEFAULT NULL,

									 `sname` varchar(30) DEFAULT NULL,

									 `cid` int(11) DEFAULT NULL

									) ENGINE=MyISAM DEFAULT CHARSET=latin1

									1 row in set (0.00 sec)

									ERROR: 

									mysql> drop table class,stu;

									Query OK, 0 rows affected (0.01 sec)

									mysql> show tables;

									Empty set (0.00 sec)

									#这样删除会出错，不要这样删除

									[root@serv01 databackup]# rm -rf /usr/local/mysql/data/larrydb/*

									[root@serv01 databackup]# rm -rf /usr/local/mysql/data/larrydb/

第五步，恢复数据

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									[root@serv01 databackup]# cp larrydb /usr/local/mysql/data/ -arvf

									`larrydb' -> `/usr/local/mysql/data/larrydb'

									`larrydb/stu.MYI' -> `/usr/local/mysql/data/larrydb/stu.MYI'

									`larrydb/stu.MYD' -> `/usr/local/mysql/data/larrydb/stu.MYD'

									`larrydb/stu.frm' -> `/usr/local/mysql/data/larrydb/stu.frm'

									`larrydb/db.opt' -> `/usr/local/mysql/data/larrydb/db.opt'

									`larrydb/class.frm' -> `/usr/local/mysql/data/larrydb/class.frm'

									mysql> use larrydb;

									Database changed

									mysql> show tables;

									+-------------------+

									| Tables_in_larrydb |

									+-------------------+

									| class       |

									| stu        |

									+-------------------+

									2 rows in set (0.00 sec)

									mysql> select * from class;

									ERROR 1146 (42S02): Table 'larrydb.class' doesn't exist

									mysql> select * from stu;

									+------+---------+------+

									| sid | sname  | cid |

									+------+---------+------+

									|  1 | larry01 |  1 |

									|  2 | larry02 |  2 |

									+------+---------+------+

									2 rows in set (0.00 sec)

									mysql> drop database larrydb;

									Query OK, 2 rows affected (0.00 sec)

									#再次导入

									[root@serv01 databackup]# mysql -uroot -p123456 < larrydb.sql

									mysql> use larrydb;

									Database changed

									mysql> show tables;

									+-------------------+

									| Tables_in_larrydb |

									+-------------------+

									| class       |

									| stu        |

									+-------------------+

									2 rows in set (0.00 sec)

									mysql> select * from stu;

									+------+---------+------+

									| sid | sname  | cid |

									+------+---------+------+

									|  1 | larry01 |  1 |

									|  2 | larry02 |  2 |

									+------+---------+------+

									2 rows in set (0.00 sec)

									mysql> select * from class;

									+------+--------+

									| cid | cname |

									+------+--------+

									|  1 | linux |

									|  2 | oracle |

									+------+--------+

									2 rows in set (0.00 sec)