raid config

Here is the situation: I have an xServe RAID with seven modules on the upper and seven modules on the lower controller. I would like to use the upper controller as a production RAID 5 array and have all of that data mirrored onto the lower controllers array. How or better yet .... what is the best way to accomplish this? I have heard bad things about 51, but have no experience in it. Will it be destined to fail if I do this? I am open to suggestions as well.