Lets talk Drobo.
Its a great little backup addon to you computer system. If you have a Mac its great for your time machine backups.
I use the Drobo FS on my network to backup all my computers over the network using drobo copy. This is my secondary backup source. My primary backup source is a
Drobo 4bay firewire 800 / usb2 connected and this is the one that the time machine backup uses.
Yes it is double redundancy. You can never have too much safety. However this system takes care of its self. Why not just use a regular mirrored or raid box. The answer
to that is flexabilty. With the Drobo systems you can add drives of different sizes and it uses the whole drive. In a regular raid system you must have drives of all the same size. Anyway this is what I have found over my many years in the computer photography business.
If you have any questions. Please give me an email. www.drobo.com
Drobo FS holds up to 5 drives and has and Gigabit Ethernet connection
Drobo S hold up to 4 drives and has USB3, eSATA and Firewire 800 connections