用一句话概括冷备，就是把数据库服务，比如MySQL，Oracle停下来，然后使用拷贝、打包或者压缩命令对数据目录进行备份。如果数据出现异常，则可以通过备份数据恢复。冷备一般需要定制计划，比如什么时候做备份，每次对哪些数据进行备份等等。但是由于这样的备份占用过多的空间，对大数据量的环境下不一定适合，故生产环境很少使用。

冷备示意图

冷备实验

第一步，创建测试数据库，插入测试数据

mysql> use larrydb;Database changedmysql> show tables;+-------------------+| Tables_in_larrydb |+-------------------+| access |+-------------------+1 row in set (0.00 sec)mysql> drop table access;Query OK, 0 rows affected (0.00 sec)mysql> clearmysql> show tables;Empty set (0.00 sec)mysql> mysql> create table class( -> cid int, -> cname varchar(30));Query OK, 0 rows affected (0.01 sec)mysql> show create table class \G;*************************** 1. row *************************** Table: classCreate Table: CREATE TABLE `class` ( `cid` int(11) DEFAULT NULL, `cname` varchar(30) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=latin11 row in set (0.00 sec)ERROR: No query specifiedmysql> create table stu( -> sid int, -> sname varchar(30), -> cid int) engine=myisam;Query OK, 0 rows affected (0.00 sec)mysql> show create table stu \G;*************************** 1. row *************************** Table: stuCreate Table: CREATE TABLE `stu` ( `sid` int(11) DEFAULT NULL, `sname` varchar(30) DEFAULT NULL, `cid` int(11) DEFAULT NULL) ENGINE=MyISAM DEFAULT CHARSET=utf81 row in set (0.00 sec)ERROR: No query specifiedmysql> insert into class values(1,'linux'),(2,'oracle');Query OK, 2 rows affected (0.00 sec)Records: 2 Duplicates: 0 Warnings: 0mysql> desc class;+-------+-------------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+-------+-------------+------+-----+---------+-------+| cid | int(11) | YES | | NULL | || cname | varchar(30) | YES | | NULL | |+-------+-------------+------+-----+---------+-------+2 rows in set (0.00 sec)mysql> desc stu;+-------+-------------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+-------+-------------+------+-----+---------+-------+| sid | int(11) | YES | | NULL | || sname | varchar(30) | YES | | NULL | || cid | int(11) | YES | | NULL | |+-------+-------------+------+-----+---------+-------+3 rows in set (0.00 sec)mysql> insert into stu values(1,'larry01',1),(2,'larry02',2);Query OK, 2 rows affected (0.00 sec)Records: 2 Duplicates: 0 Warnings: 0mysql> select * from stu;+------+---------+------+| sid | sname | cid |+------+---------+------+| 1 | larry01 | 1 || 2 | larry02 | 2 |+------+---------+------+

第二步，停掉MySQL

[root@serv01 ~]# /etc/init.d/mysqld stopShutting down MySQL... SUCCESS!

第三步，创建备份目录，并修改拥有者和所属组

[root@serv01 ~]# mkdir /databackup[root@serv01 ~]# chown mysql.mysql /databackup/ -R[root@serv01 ~]# ll /databackup/ -ddrwxr-xr-x. 2 mysql mysql 4096 Sep 10 17:46 /databackup/[root@serv01 ~]# cd /databackup/

第四步，冷备（使用tar命令）

[root@serv01 databackup]# tar -cvPzf mysql01.tar.gz

第五步，测试冷备的数据是否正常，我们删除掉data下的所有数据

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

第六步，删除所有数据后数据库不能启动

[root@serv01 databackup]# /etc/init.d/mysqld startStarting MySQL.. ERROR! The server quit without updating PID file (/usr/local/mysql/data/serv01.host.com.pid).

第七步，恢复数据（使用tar命令）

[root@serv01 databackup]# tar -xvPf mysql01.tar.gz

第八步，启动MySQL，然后登录MySQL，查看数据是否丢失，如果数据正常代表冷备成功

[root@serv01 databackup]# /etc/init.d/mysqld startStarting MySQL.. SUCCESS! [root@serv01 ~]# mysqlWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 1Server version: 5.5.29-log Source distributionCopyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.mysql> use larrydb;Database changedmysql> select * from class;+------+--------+| cid | cname |+------+--------+| 1 | linux || 2 | oracle |+------+--------+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)

以上就是实现MySQL冷备的全部过程，大家对冷备有没有了大概的了解，希望这篇文章可以对大家的学习有所帮助。