NAS hard disk and backup?

["Ho Yin Ng" <architect.hoyin@xxxxxxxxx>]

Also about to buy a NAS device, probably a 500GB. a 1TB is a bit too
much for me at the moment.

However I just want to check ho backups are made.  Can they be done to
another disk attached to it via USB? OR does it require a computer
within the network to be on to do a backup?

Ideally I want something that can be conducted independent of a
computer. Another advantage would be if the NAS to backup some
selected folders to an FTP?

Am I dreaming or is there something out there like this?

Any advice on what make to go for? I need something quiet and
something that does not produce too much heat!

Thanks

Ho yin