How To Reinstall MySQL Server v5.x On Linux

Question: I would like to delete my old MySQL server because its database has been corrupted due to which I want to reinstall MySQL database server. How can I reinstall fresh full MySQL server again?

Answer: If your database has been corrupted and want to reinstall mysql server, you can easily do this, just follow the the below steps.

Step #1: Backup Database And Configuration Files

First of all take database backup and its related files before reinstalling MySQL server.

You will need to backup:

• MySQL database data directory such as ” /var/lib/mysql/ ” it is default data directory path. For backup you can use mysqldump command.
• MySQL configuration files “/etc/my.cnf, /etc/logrotate.d/mysqld and other related files.
• MySQL log Files like “/var/log/mysqld.log“.

Backup all MySQL related files on RHEL/CentOS/Fedora based systems.

# mkdir /root/mysql-bkp/
# tar zcvf /root/mysql-bkp/mysql_all_config_bkp.dd-mm-yyyy.tar.gz /etc/logrotate.d/mysqld /var/log/mysqld.log /etc/my.cnf /root/my.cnf /var/lib/mysql/

Backup MySQL Databases

For MySQL database backup you can use below script “database_bkp.sh“.

#!/bin/sh
# database_bkp.sh: Dump MySQL databases.
# Note: Tested only on RHEL/CentOS/Debian/Ubuntu Linux.
# Author: looklinux 
# -----------------------------------------------------
# (1) set up all the mysqldump variables
BAK=/root/mysql-bkp/
FILE=XXX_db.sql.`date +"%Y%m%d"`
DBSERVER=127.0.0.1
DATABASE=XXX
USER=XXX
PASS=XXX

# (2) in case you run this more than once a day, remove the previous version of the file
unalias rm     2> /dev/null
rm $BAK/${FILE}     2> /dev/null
rm $BAK/${FILE}.gz  2> /dev/null

# (3) do the mysql database backup (dump)

# use this command for a database server on a separate host:
#mysqldump --opt --protocol=TCP --user=${USER} --password=${PASS} --host=${DBSERVER} ${DATABASE} > $BAK/${FILE}

# use this command for a database server on localhost. add other options if need be.
mysqldump --opt --user=${USER} --password=${PASS} ${DATABASE} > $BAK/${FILE}

# (4) gzip the mysql database dump file
gzip $BAK/$FILE

# (5) show the user the result
echo "${FILE}.gz was created:"
ls -l $BAK/${FILE}.gz

Now set the execute permission on script file.

# chmod +x database_bkp.sh

Now execute below command to take backup.

# ./database_bkp.sh

You will get some output like below.

XXX_db.sql.08-03-2017-04:00:18.gz was created:
-rw-r--r--. 1 root root  1836687 Mar  8 04:00 XXX_db.sql.08-03-2017-04:00:18.gz

Step #2 : Remove/Erase MySQL Server

After creating a database and its configuration backup, delete MySQL server using below command.

On Debian/Ubuntu systems

$ sudo apt-get purge mysql-server mysql-common mysql-client

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package mysql-client is not installed, so not removed
The following packages were automatically installed and are no longer required:
  libnet-daemon-perl libdbi-perl libterm-readkey-perl mysql-server-core-5.5 mysql-client-core-5.5
  libplrpc-perl
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
  libdbd-mysql-perl* libmysqlclient18* mysql-client-5.5* mysql-common* mysql-server*
  mysql-server-5.5*
0 upgraded, 0 newly installed, 6 to remove and 2 not upgraded.
After this operation, 67.3 MB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 82128 files and directories currently installed.)
Removing mysql-server ...
Removing mysql-server-5.5 ...
mysql stop/waiting
Purging configuration files for mysql-server-5.5 ...
Removing mysql-client-5.5 ...
Removing libdbd-mysql-perl ...
Removing libmysqlclient18 ...
Purging configuration files for libmysqlclient18 ...
Removing mysql-common ...
Purging configuration files for mysql-common ...
dpkg: warning: while removing mysql-common, directory '/etc/mysql' not empty so not removed.
Processing triggers for man-db ...
Processing triggers for ureadahead ...
Processing triggers for libc-bin ...
ldconfig deferred processing now taking place

Now delete database and its configuration files like below.

$ sudo rm -rvf /var/lib/mysql /etc/mysql/ /var/log/mysql*

On RHEL/CentOS/Fedora system

# yum remove mysql mysql-server

Loaded plugins: product-id, rhnplugin, security, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
This system is receiving updates from RHN Classic or RHN Satellite.
Setting up Remove Process
Resolving Dependencies
--> Running transaction check
---> Package mysql.x86_64 0:5.1.71-1.el6 will be erased
---> Package mysql-server.x86_64 0:5.1.71-1.el6 will be erased
--> Finished Dependency Resolution
 
Dependencies Resolved
 
======================================================================================================
 Package                Arch             Version                Repository                       Size
======================================================================================================
Removing:
 mysql                  x86_64           5.1.71-1.el6           @rhel-x86_64-server-6           2.4 M
 mysql-server           x86_64           5.1.71-1.el6           @rhel-x86_64-server-6            25 M
 
Transaction Summary
======================================================================================================
Remove        2 Package(s)
 
Installed size: 27 M
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing    : mysql-server-5.1.71-1.el6.x86_64                                                   1/2 
  Erasing    : mysql-5.1.71-1.el6.x86_64                                                          2/2 
  Verifying  : mysql-server-5.1.71-1.el6.x86_64                                                   1/2 
  Verifying  : mysql-5.1.71-1.el6.x86_64                                                          2/2 
 
Removed:
  mysql.x86_64 0:5.1.71-1.el6                    mysql-server.x86_64 0:5.1.71-1.el6                   
 
Complete!

Now delete database and its configuration files like below.

# rm -rvf /etc/my.cnf /var/lib/mysql/ /var/log/mysqld.log

Step #3: Reinstall MySQL Server

Now install MySQL fresh server using below command.

On RHEL/CentOS/Fedora Systems

# yum install mysql mysql-server

On Debian/Ubuntu Systems

$ sudo apt-get install mysql-client mysql-server mysql-common

Restart MySQL server

Restart MySQL Server if not started.

# service mysqld start

Step #4: Restore Databases And Configuration Files

Follow the below steps to restore all databases and its related files.

Restore all databases

# gunzip XXX_db.sql.08-03-2017-04:00:18.gz
# mysql -u root -p password -e 'CREATE DATABASE XXX;'
# mysql -u root -p XXX < XXX_db.sql.08-03-2017-04\:00\:18

Restore all MySQL related configuration files

# mkdir /root/backups
# tar xvf /root/mysql-bkp/mysql_all_config_bkp.dd-mm-yyyy.tar.gz -C /root/backups/
# cp /root/backups/etc/my.cnf /etc

Restart MySQL server

# service mysqld restart

I hope this article will help to reinstall MySQL server on Linux and Unix based systems. If you have any queries and problem please comment in comment section.

Thanks:)