How to backup to external drive

I use super duper and time machine to backup my mac. I would like to also specifically backup devonthink pro office to its own separate hard drive. I’m sure it’s basic, but I can’t find out how to do it. I want every bit of data from the entire database, not just a directory or listing.

Any suggestions?

I use Synk pro to do it. http://decimus.net/Synk/