Today's blog in the Robert's Rules of Exchange is pretty good. The MSExchangeTeam explains the different disk technologies that can be used with some examples. Really good stuff.
Bear in mind that if you are really considering JBOD you need at least 3 copies of your database in your DAG.
In this post, we want to discuss some of the thought process you should have as you decide what your storage infrastructure is for Exchange 2010. Further, we will discuss how and why you should test your storage. These processes belong early in the planning stages for Exchange 2010, because if you don't test your storage before moving users to that storage, it is a lot more painful to fix than if you could fix something without affecting users.
Read more at source: http://msexchangeteam.com/archive/2011/01/07/457471.aspx