Powershell script to backup all the site collections in the sharePoint Farm.

Below is the link to powershell script that does the backup of all the site collections in the SP farm.

http://practicalkungfu.net/2011/11/14/sharepoint-2010-backup-all-site-collections-in-all-web-applciations/

I have tested this script and works great. you just need to change your path where you will be running the backups and make sure you provide adequate access to the user.

It also does the deletion after certain no of days. It has 30 days by default but you can change it accordingly to your needs.