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
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mysql> use larrydb;
Database changed
mysql> 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> clear
mysql> 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 : 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> 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 : 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=utf8
1 row in set (0.00 sec)
ERROR:
No query specified
mysql> insert into class values (1, 'linux' ),(2, 'oracle' );
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> 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: 0
mysql> select * from stu;
+ ------+---------+------+
| sid | sname | cid |
+ ------+---------+------+
| 1 | larry01 | 1 |
| 2 | larry02 | 2 |
+ ------+---------+------+
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第二步,停掉MySQL
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[root@serv01 ~]# /etc/init.d/mysqld stop
Shutting down MySQL... SUCCESS!
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第三步,创建备份目录,并修改拥有者和所属组
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[root@serv01 ~]# mkdir /databackup
[root@serv01 ~]# chown mysql.mysql /databackup/ -R
[root@serv01 ~]# ll /databackup/ -d
drwxr-xr-x. 2 mysql mysql 4096 Sep 10 17:46 /databackup/
[root@serv01 ~]# cd /databackup/
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第四步,冷备(使用tar命令)
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[root@serv01 databackup]# tar -cvPzf mysql01.tar.gz
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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
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[root@serv01 databackup]# rm -rf /usr/ local /mysql/data/*
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第六步,删除所有数据后数据库不能启动
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[root@serv01 databackup]# /etc/init.d/mysqld start
Starting MySQL.. ERROR! The server quit without updating PID file (/usr/ local /mysql/data/serv01.host.com.pid).
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第七步,恢复数据(使用tar命令)
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[root@serv01 databackup]# tar -xvPf mysql01.tar.gz
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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
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[root@serv01 databackup]# /etc/init.d/mysqld start
Starting MySQL.. SUCCESS!
[root@serv01 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.29-log Source distribution
Copyright (c) 2000, 2012, Oracle and / or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and / or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use larrydb;
Database changed
mysql> 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。