用一句話概括冷備，就是把數據庫服務，比如MySQL，Oracle停下來，然后使用拷貝、打包或者壓縮命令對數據目錄進行備份。如果數據出現異常，則可以通過備份數據恢復。冷備一般需要定制計劃，比如什么時候做備份，每次對哪些數據進行備份等等。但是由于這樣的備份占用過多的空間，對大數據量的環境下不一定適合，故生產環境很少使用。
冷備示意圖
冷備實驗
第一步，創建測試數據庫，插入測試數據
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，創建備份目錄，并修改擁有者和所屬組
[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，冷備（使用tar命令）
[root@serv01 databackup]# tar -cvPzf mysql01.tar.gz
第五步，測試冷備的數據是否正常，我們刪除掉data下的所有數據
[root@serv01 databackup]# rm -rf /usr/local/mysql/data/*
第六步，刪除所有數據后數據庫不能啟動
[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，恢復數據（使用tar命令）
[root@serv01 databackup]# tar -xvPf mysql01.tar.gz
第八步，啟動MySQL，然后登錄MySQL，查看數據是否丟失，如果數據正常代表冷備成功
[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)
以上就是實現MySQL冷備的全部過程，大家對冷備有沒有了大概的了解，希望這篇文章可以對大家的學習有所幫助。
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