[Drupal] multi site with subdomain running the same code in Drupal

I have a default site with url www.example.com, and now I want to build another subsite with subdomain mysite.example.com.

1. Set the folder of the submain.

Create a folder mysite.example.com under sites, that is sites/mysite.example.com. Be aware of the name of the folder, because I want to create the a subdomain as mysite.example.com, so I have to set the name as "mysite.example.com".

And the copy the file from sites/default/default.settings.php to sites/mysite.example.com/default.settings.php, and rename it to settings.php.

2. Set the hosts.

Modify the hosts file. Add the following code:

127.0.0.1  www.example.com
127.0.0.1   mysite.example.com

3. Set the virtualHost

Modify the httpd.conf file.

NameVirtualHost *:80
<VirtualHost *:80>
    <Directory "/media/MyDocuments/xampp/htdocs/drupal">
    </Directory>

    DocumentRoot "/media/MyDocuments/xampp/htdocs/drupal"
    ServerName www.example.com
    ServerAlias www.example.com mysite.example.com
</VirtualHost>

4. Set the clean urls

Modify the .htaccess file under the root folder, key codes as :

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} ^/~kerunt/site/mysite
RewriteRule ^(.*)$ mysite/index.php?q=$1 [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !=/favicon.ico
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

Ok, now you can visit the url mysite.example.com and build a new subsite with the same code!

Have fun!