How to recover MySQL when the HDD on an older Linux server fails

This is Haraoka from Beyond

We have put together a simple summary of the steps to recover not only data files but also MySQL data when your old server will no longer boot due to hard disk damage

This guide will show you how to recover data from MySQL 3.23.58.
*Please note that data recovery involves various factors, so this guide is for reference only.*

Have your data recovered by a hard disk recovery company

First, you need to restore the failed HDD

It may be possible to recover the data yourself as described below, but if you fail, the situation may worsen, so if the data contains business data or other data, it is best to use a hard disk recovery service to ensure the data is recovered as reliably as possible

How to repair and recover data from an HDD, even for amateurs:
http://macasakr.sakura.ne.jp/HDD

There are many different companies out there, but my recommendation is Kumanan PC Net.
https://www.kumanan-pcnet.co.jp/hdd/info.php

In fact, there are significant differences in technical ability among companies, but Kumanan PC Net has 15 years of experience, has its own clean room, and provides recovery services based on high technical skills

Build a recovery server

• Preparing the server for building

We will prepare a suitable chassis and build a server for database recovery. First, we will check the OS version of the server on which MySQL was running

cat /recovery_directory/etc/redhat-release

in the directory of the recovered data
check the `redhat-release` file

Older operating systemsi386ori686 processors. While it's possible to install a 32-bit OS on a 64-bit CPU, it will only recognize up to 4GB of memory, so it's best to remove any excess memory from cases with a larger configuration.

• Installing an older version of Linux OS

This time, I'm using CentOS as a reference:
http://www.linuxmaster.jp/linux_blog/2010/03/centos.html

Download it from this site:
http://vault.centos.org/
This is a great site where you can download CentOS 2.1 and later.
This time, I downloaded CentOS 4.

Download MySQL

I borrowed the installation files from here:
http://dbstudy.info/mysql/

It's also available here:
http://live.dadanini.at/mysql/downloads_html/mysql-3.23.html

Install MySQL

Build from source files

• Creating the installation directory and user

cd /usr/local/src/ /usr/sbin/groupadd mysql /usr/sbin/useradd -g mysql mysql mkdir /usr/local/mysql mkdir /usr/local/mysql/var/ chown -R mysql:mysql /usr/local/mysql

• Installing MySQL

tar -zxvf mysql-3.23.58.tar.gz cd mysql-3.23.58/ ./configure --prefix=/usr/local/mysql make make install

• Creating an installation database

scripts/mysql_install_db

• mysql start

/usr/local/mysql/bin/safe_mysqld --user=mysql &

*Please note that this is not mysqld_safe

• Startup check

ps -ef | grep mysql

• Try logging in (no password)

mysql -u root

• Set the root password

mysqladmin -u root password "＊＊＊＊＊"

• mysql stop

/usr/local/mysql/bin/mysqladmin -u root -p shutdown

Now you're ready to restore

Replace the recovered data file

Upload the entire MySQL data file from the HDD recovery destination

There is a possibility that the characters may be garbled, so it is better to compress and move the file if possible

• Unzip the uploaded file

gunzip /home/hogehoge/mysql_buckupdata.gz

• Move entire directory of data files

mv /usr/local/mysql/var /usr/local/mysql/var_tmp cp /home/hogehoge/mysql_buckupdata /usr/local/mysql/var

• Permission Change

chown -R mysql:mysql /usr/local/mysql/var

• Delete iblogfile

rm /usr/local/mysql/var/ib_logfile*

• Starting the DB

mysql start/stop

/usr/local/mysql/bin/mysqld_safe --user=mysql &

If it starts up like this, recovery is OK for now

Exporting the DB

mysqldump -u root -p db name > /home/hogehoge/new_buckup.dmp

Export the recovered data

This completes the data recovery

If you have any problems with recovery, please contact Beyond

https://beyondjapan.com/contact