How to Change Mysql Data Directory

Here I am going to move my default mysql data directory (/var/lib/mysql on RHEL5) to a new directory /mysqldata.

First, we must stop the mysql service before doing next step.

# /etc/init.d/mysql stop

we need to create a directory that will be the new databases location.

# mkdir /mysqldata

Now copy the existing data directory (/var/www/mysql ) to /mysqldata.

# cp –pvr /var/www/mysql/* /mysqldata/

Change the ownership of /mysqldata recursivly to mysql user and group.

# chown -R mysql:mysql /mysqldata

Now we need to make the following changes in /etc/my.cnf so that it can make point to new data directory.

# vim /etc/my.cnf

datadir = /mysqldata

socket = /mysqldata/mysql.sock

Finally start the mysql server

#/etc/init.d/mysql start

If mysql server start without any error or warning your data directory has been moved successfully. Now all the database files will be managed under new data directory, here is some steps to verify the same :-

Login to mysql server

#mysql –u root –pmysqlpassword

mysql> create database newdb;

mysql> exit;

Now list all the databases under /mysqldata directory.Mysql should store newly created datrabase under /mysqldata.

#ls -ltr /mysqldata

rw-rw---- 1 mysql mysql 10485760 2010-04-22 10:05 ibdata1

-rw-rw---- 1 mysql mysql 5242880 2010-04-22 10:05 ib_logfile0

-rw-rw---- 1 mysql mysql 5242880 2010-04-22 09:49 ib_logfile1

drwx------ 2 mysql mysql 4096 2010-04-22 09:49 mysql

srwxrwxrwx 1 mysql mysql 0 2010-04-22 10:05 mysql.sock

drwx------ 2 mysql mysql 4096 2010-04-22 09:49 test

drwx------ 2 mysql mysql 4096 2010-05-03 11:39 newdb (newly created database)

How To Install Apache Server on Linux

Apache HTTP Server is an open source HTTP web server for Unix platforms (BSD, GNU/Linux, and UNIX systems), Microsoft Windows, and other platforms. The Apache HTTP Server is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

Note: Here I am installing apache2.2 on Red Hat Linux 5

Download the following rpms:

#wget http://www.apache.org/dist/httpd/binaries/rpm/i386/httpd-2.2.3-1.i386.rpm  

#wget http://www.apache.org/dist/httpd/binaries/rpm/i386/httpd-devel-2.0.59-1.i386.rpm

#wget http://www.apache.org/dist/httpd/binaries/rpm/i386/httpd-manual-2.0.59-1.i386.rpm

Installation:

Type the following command if you are using Rhel, Fedora or Centos.

# rpm –ivh httpd-2.2.3-1.i386.rpm

# rpm –ivh httpd-devel-2.2.3-1.i386.rpm

# rpm –ivh httpd-manual-2.2.3-1.i386.rpm

You can also use yum command to install the same, but you will need yum repository for that

Running Apache:

Now we need to start httpd daemon to get it working

# /etc/init.d/httpd start

You can stop the server at any time by

# /etc/init.d/httpd stop

After making changes to the configuration file of apache, you will need to restart the server:

# /etc/init.d/httpd restart

To restart Apache without aborting current connections

#etc/init.d/httpd graceful

To Start Apache on system startup:

#chkconfig httpd on

After making changes in httpd.conf you can check the configuration syntax.

#etc/init.d/httpd configtest

Verify the Installation:

Open http://localhost in your browser, It will open following page.

If you can see this, it means that the installation of the Apache web server on this System was successful. Default document root for Apache is /var/www/html.You may now add content to this directory and replace this page.

Installation of PhpMyAdmin

First thing we need to do is to download the latest phpmyadmin package you can download the package with wget command 
#cd /download
# wget http://sourceforge.net/projects/phpmyadmin/files/phpMyAdmin/3.2.3/phpMyAdmin-3.2.3-all-languages.zip/download

Now we need to move the downloaded package to apache document root directory to make it accessible through web interface.
# mv phpMyAdmin-3.2.2-all-languages.tar.gz /var/www/html/
 Extract the tar.gz file:-
# cd  /var/www/html/
# tar –xvzf phpMyAdmin-3.2.2-all-languages.tar.gz
Rename exracted folder to phpmyadmin. 
# mv phpMyAdmin-3.2.2-all-languages phpmyadmin
Change owner to apache user
# chown –R apache:apache phpmyadmin
# cd phpmyadmin
Now we need to create a config directory temporarily and give write access .
# mkdir config
# chmod 755 config
# cp config.sample.inc.php config/config.inc.php

Open web browser and point to the following URL.
http://192.168.10.2/phpmyadmin/setup
It will open the initial setup page clickon New Server in the Server Section.
Enter Hostname:- localhost # default(localhost)
Server port: 3306 #default(3306)
Server Socket: - /var/lib/mysql/mysql.sock #default (/var/lib/mysql/mysql.sock)
Connection type: tcp
PHP extension to use: Mysqli
Authentication type: cookie
User for config auth: root
Password for config auth: ******* #mysql root password)
Click on the Save button in the Configuration section and close the browser window



Move config.inc.php to phpmyadmin parent directory
# mv config/config.inc.php /var/www/html/phpmyadmin/
Delete the config directory as we don't need this directory anymore
# rm –rf /var/www/html/phpmyadmin/config



Finally phpmyadmin has been  installed, point your browser to the following URL. 
 http://192.168.1.2/phpmyadmin

You should be able to login with your mysql user.

MySql Installation on Linux Guide

Download the required packages.

http://mirror.cogentco.com/pub/mysql/MySQL-5.2/

Installing MySql :-

# rpm -ivh MySQL-devel-5.2.0-0.glibc23.i386.rpm

# rpm -ivh MySQL-client-5.2.0-0.glibc23.i386.rpm

# rpm -ivh MySQL-server-5.2.0-0.glibc23.i386.rpm

# rpm -ivh MySQL-shared-5.2.3-0.glibc23.i386.rpmc23

# /etc/init.d/mysql start

Starting MySQL [OK]

Note:- If you get any error or fail to start mysql.

# /etc/init.d/mysql start

Starting MySQL [Failed]

Ø Then Check the following things.

# sestatus

must be disabled

# vim /selinux/config

SELINUX=disabled

# /etc/init.d/iptables stop

#ps -ef | grep mysql
#kill -9 (pid of mysql process)

Now Start Mysql :

#/etc/init.d/mysql start

Starting MySQL [OK]

Copy the sample my.cnf file to /etc directory

# cp /usr/share/mysql/my-medium.cnf /etc/my.cnf

Set Mysql root user password:

# mysqladmin -u root password mypassword

Login to Mysql Database server

# mysql –u root –pmypassword

mysql>

Once MySQL client is running, you should get the mysql> prompt. Type the following at this prompt:

mysql>show databases;

You will now get a list of databases like:

+----------------+

| Database       |

+----------------+

| mysql          |

| test           |

+----------------+

2 rows in set (0.00 sec)

Let's create a database!

mysql> create database databasename;

Check databases:

mysql>show databases;

+-------------+

| Database    |

+-------------+

|databasename |  

| mysql       |

| test        |

+-------------+

Connecting to database:

mysql>use databasename;

Checking Tables:

mysql>show tables;;

Reading Tables:

mysql>describe tablename;

Show All data in Table:

mysql> SELECT * FROM tablename;

You will get the output something like:-

+-------------+---------+------+-----+---------+-------+

| Field       | Type    | Null | Key | Default | Extra |

+-------------+---------+------+-----+---------+-------+

| abc         | text    |      |     |         |       |

| ghi        | text    |      |     |         |       |

+-------------+---------+------+-----+---------+-------+

2 rows in set (0.00 sec)

Deleting a database:

mysql>drop database databasename;

Deleting a table:

mysql>use databasename;

mysql>drop table tablename;

Creating Mysql User and setting permissions:

mysql> create user 'username'@'localhost' IDENTIFIED BY 'password';

mysql> grant all on *.* TO 'username'@'localhost' IDENTIFIED BY 'password';

mysql> flush privileges;

Backup of Mysql Database:-

# mysqldump –u root –pmypassword databasename > databasename.sql

Restore Mysql database:

# mysql –u root –pmypassword databasename < style="">

Backup of single table in Mysql :-

# mysqldump –u root –pmypassword databasename tablename > tablename.sql

Restore of single table in Mysql :-

# mysql –u root –pmypassword databasename tablename < style="">

Installation of Nagios on Linux

Download the following packages

• nagios-3.0.1.tar.gz
• nagios-plugins-1.4.11.tar.gz

Verify the following installed packages:

      gcc-3.4.6-8

      compat-gcc-32-3.2.3-47.3

      libgcc-3.4.6-8

      compat-libgcc-296-2.96-132.7.2

      compat-gcc-32-c++-3.2.3-47.3

      gcc-c++-3.4.6-8

      gd-2.0.28-5.4E

Create user and group for Nagios

# useradd nagios

# passwd nagios

# groupadd nagcmd

# usermod -G nagcmd nagios

# usermod -G nagcmd apache

Installation of nagios

 # tar xvf nagios-3.0.1.tar.gz

# cd nagios-3.0.1

# ./configure --with-command-group=nagcmd   --with-cgiurl=/nagios/cgi-bin

# make all

# make install

# make install-init

# make install-config

# make install-commandmode

# make install-webconf

Installion of nagios plugins:

# tar xvf nagios-plugins-1.4.11.tar.gz

# cd nagios-plugins-1.4.11

# ./configure --with-nagios-user=nagios --with-nagios-group=nagios

# make

# make install

Add nagios to start at boot:

# chkconfig --add nagios

# chkconfig nagios on

Nagios User Authentication:

# htpasswd -c /usr/local/nagios/etc/htpasswd  nagiosadmin

Verify Nagios Configuration:

# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

Starting Nagios:

# /etc/init.d/nagios start

Login to web interface : http://localhost/nagios/