Hi Saeed,

There are quite some ways to make back-ups, such as through init.d in Linux, via the postgreSQL database itself or through Odoo modules. The most easy way (especially for non-technical people) is to use a module which you can configure to take backups every xx time. I've written a module for this, which you can find here: https://www.odoo.com/apps/modules/8.0/auto_backup/ and I also wrote a tutorial on how to use it: http://www.odoo.yenthevg.com/automated-backups-in-odoo/

 Yenthe