Have you just ordered a new Mac? Today, Apple posted a Knowledge Base article regarding the new Fusion Drive for the refreshed iMac and Mac mini.
The storage technology, which was launched this past Tuesday, combines flash and traditional hard drive technology to create a hybrid system that "combines the performance of Flash storage with the capacity of a hard drive."
According to the FAQ, Fusion Drive requires a special version of Disk Utility. This release is "unique," and Apple mentions that you cannot use older Disk Utility releases with the new setup.
Fusion Drive will allow users to add at most one extra partition.