My Drobo has two partitions: one for Time Machine and the another for SuperDuper bootable backup. Suppose the main HD inside my iMac fails. If I plug the DROBO on my Macbook, will the DROBO be recognized by the Macbook? In this case, how can I have access to the data on it?
It mounts like any other USB mass-storage device (ie, portable hard drive).
So, can I format the main hard drive and after that recover all data from DROBO?
Sure, as long as SuperDuper supports booting in some way, can read from a USB drive formatted with whatever filesystem you formatted your Drobo with (likely HFS+), then it’s the same as if you had your backups stored on a regular USB drive.
Thank you bhiga. I’ve never had any problem so I’m learning to get back all my data before it happens to me. Thanks again.
Always best to be prepared before you need the skills!
DEFINITELY the right way to do things, and refreshing to read in a sea of “oh crap, this got screwed up!” 
If you have a spare hard drive, you could even test your whole restore strategy now, before the crisis happens.