在上一篇文章中我們提到熱備，熱備也就是在MySQL或者其他數據庫服務在運行的情況下進行備份。本文分享另外一種備份的方法，也就是熱拷貝。熱拷貝跟熱備很類似，只不過熱備使用mysqldump命令，熱拷貝使用mysqlhotcopy命令。熱拷貝的優勢在于支持服務運行中進行備份，速度快，性能好；劣勢在于只能備份MyIsam的表，無法備份InnoDB的表。所以在生產環境中應該酌情使用。
示意圖
熱備模擬
第一步，熱拷貝
[root@serv01 databackup]# mysqlhotcopy -uroot -p123456 --database larrydb > larrydb_hostcopy.sqlCan'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，報錯。因為這個命令是用perl寫的或者此命令需要perl支持，所以需要安裝perl
[root@serv01 databackup]# yum install perl* -y
第三步，對數據庫larrydb熱拷貝
[root@serv01 databackup]# mysqlhotcopy --help
#第一種寫法
[root@serv01 databackup]# mysqlhotcopy --user=root --password=123456 larrydb /databackup/
#第二種寫法
[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，模擬數據丟失
[root@serv01 databackup]# ll larrydbtotal 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.MYImysql> use larrydb;Database changedmysql> show tables;+-------------------+| Tables_in_larrydb |+-------------------+| class || stu |+-------------------+2 rows in set (0.00 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> 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=latin11 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) #這樣刪除會出錯，不要這樣刪除[root@serv01 databackup]# rm -rf /usr/local/mysql/data/larrydb/*[root@serv01 databackup]# rm -rf /usr/local/mysql/data/larrydb/
第五步，恢復數據
[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 changedmysql> 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 existmysql> 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)#再次導入[root@serv01 databackup]# mysql -uroot -p123456 < larrydb.sqlmysql> use larrydb;Database changedmysql> 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)
本文介紹了另一種備份--熱拷貝，與熱備的區別在于使用的命令不同，熱拷貝使用mysqlhotcopy命令，希望大家可以親自動手操作一下！
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