Backup exec 2012 and storage device

Hi

I want use a server HP for my backup, it is a good idea use this server for disk target (with FreeNas  installed and backup exec server installed on virtual machine)  or i need install windows 2008 and install on the server backupexec and use local disk space for disk target?

I need backup virtual machine (backup exec vray edition) and phisical machine.

Thank you.

Fabio