Backup and Restore MySQL Database using mysqlhotcopy

mysqlhotcopy is a perl script that comes with MySQL installation. This locks the table, flush the table and then performs a copy of the database. You can also use the mysqlhotcopy to automatically copy the backup directly to another server using scp.

1. mysqlhotcopy command:

[local-host]# /usr/bin/mysqlhotcopy -u root -p My2Secure$Password sugarcrm /home/backup/database --allowold --keepold

　　

The above example, performs a backup of sugarcrm, a MySQL database to the /home/backup/database directory.

–allowold: This options renames the old backup to {datbase-name}_old before taking a new backup. In this example, if sugarcrm backup already existing under /home/backup/database, it will move the old backup to /home/backup/database/sugarcrm_old before creating /home/backup/database/sugarcrm.

–keepold: This option instructs the mysqlhotcopy to keep the old backup (i.e the renamed _old) after the backup is completed.

View the mysqlhotcopy documentation using perldoc as shown below.

[local-host]# perldoc mysqlhotcopy

　　

Following are the available options that can be passed to mysqlhotcopy command.

Option	Description
–addtodest	Do not rename target directory (if it exists); merely add files to it
–allowold	Do not abort if a target exists; rename it by adding an _old suffix
–checkpoint=db_name.tbl_name	Insert checkpoint entries
–chroot=path	Base directory of the chroot jail in which mysqld operates
–debug	Write a debugging log
–dryrun	Report actions without performing them
–flushlogs	Flush logs after all tables are locked
–help	Display help message and exit
–host=host_name	Connect to the MySQL server on the given host
–keepold	Do not delete previous (renamed) target when done
–noindices	Do not include full index files in the backup
–password[=password]	The password to use when connecting to the server
–port=port_num	The TCP/IP port number to use for the connection
–quiet	Be silent except for errors
–regexp	Copy all databases with names that match the given regular expression
–resetmaster	Reset the binary log after locking all the tables
–resetslave	Reset the master.info file after locking all the tables
–socket=path	For connections to localhost
–tmpdir=path	The temporary directory
–user=user_name,	The MySQL username to use when connecting to the server
–version	Display version information and exit

2. mysqlhotcopy command output:

The above mysqlhotcopy command will display an output similar to the following.

[local-host]# /usr/bin/mysqlhotcopy -u root -p My2Secure$Password sugarcrm /home/backup/database --allowold --keepoldLocked 98 tables in 0 seconds.
Flushed tables (`sugarcrm`.`accounts`, `sugarcrm`.`accounts_audit`, `sugarcrm`.`accounts_bugs`) in 0 seconds.
Copying 295 files...
Copying indices for 0 files...
Unlocked tables.
mysqlhotcopy copied 98 tables (295 files) in 0 seconds (0 seconds overall).

　　

By default, MySQL database is located under /var/lib/mysql/{db-name}. mysqlhotcopy takes a backup of the table files from this default database location, to the backup directory. The backup directory /home/backup/database/sugarcrm, will contain exact copy of all the files from the real MySQL database /var/lib/mysql/sugarcrm directory.

[local-host]# ls -1 /var/lib/mysql/sugarcrm | wc -l
295
[local-host]# ls -1 /home/backup/database/sugarcrm | wc -l
295

　　

Please note that every table has three corresponding files with the extension *.frm, *.MYD and *.MYI. The database directory also contains a db.opt file that contains the database related parameter.

In the above example, you can see the mysqlhotcopy takes a backup of 98 sugarcrm database tables. So, the total number of files in the backup directory = 98 tables * 3 + 1 db configuration file = 296 files.

3. Restore from mysqlhotcopy

To restore the backup from the mysqlhotcopy backup, simply copy the files from the backup directory to the /var/lib/mysql/{db-name} directory. Just to be on the safe-side, make sure to stop the mysql before you restore (copy) the files. After you copy the files to the /var/lib/mysql/{db-name} start the mysql again.

4. Troubleshooting mysqlhotcopy

How to resolve Can’t locate DBD/mysql.pm issue? mysqlhotcopy is a perl script and it requires the perl-DBD module. You may receive the following error while executing mysqlhotcopy if perl-DBD module is not installed.

[local-host]# /usr/bin/mysqlhotcopy -u root -p My2Secure$Password sugarcrm /home/backup/database --allowold --keepoldinstall_driver(mysql) failed: Can't locate DBD/mysql.pm in @INC (@INC contains:
/usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi
/usr/lib/perl5/5.8.8 .) at (eval 7) line 3.
Perhaps the DBD::mysql perl module hasn't been fully installed,
or perhaps the capitalisation of 'mysql' isn't right.
Available drivers: DBM, ExampleP, File, Proxy, Sponge.
at /usr/bin/mysqlhotcopy line 177

　　

Make sure to install the perl-DBD package as shown below.

[local-host]# rpm -ivh perl-DBD-MySQL-3.0007-1.fc6.i386.rpm
Preparing...                ########################################### [100%]
1:perl-DBD-MySQL         ########################################### [100%]

　　

How to resolve the issue with perl-DBD installation? While installing the perl-DBD, you may get the following error message.

[local-host]# rpm -ivh perl-DBD-MySQL-3.0007-1.fc6.i386.rpm
rpmdb: Program version 4.3 doesn't match environment version
error: db4 error(-30974) from dbenv->open: DB_VERSION_MISMATCH: Database environment version mismatch
error: cannot open Packages index using db3 -  (-30974)
warning: cannot open Solve database in /usr/lib/rpmdb/i386-redhat-linux/redhat
rpmdb: Program version 4.3 doesn't match environment version
error: db4 error(-30974) from dbenv->open: DB_VERSION_MISMATCH: Database environment version mismatch
warning: cannot open Solve database in /usr/lib/rpmdb/i386-redhat-linux/redhat
error: Failed dependencies:
libmysqlclient.so.15 is needed by perl-DBD-MySQL-3.0007-1.fc6.i386
libmysqlclient.so.15(libmysqlclient_15) is needed by perl-DBD-MySQL-3.0007-1.fc6.i386

　　

Download and install the MySQL-shared-compat from mysql.com and this should resolve the above mentioned error while installing the perl-DBD package.

[local-host]# rpm -ivh MySQL-shared-compat-5.1.25-0.rhel5.i386.rpm
Preparing...                ########################################### [100%]
1:MySQL-shared-compat    ########################################### [100%]

参考：
http://www.thegeekstuff.com/2008/07/backup-and-restore-mysql-database-using-mysqlhotcopy/