...still unknown until about 18 minutes into this video.  Dream Theater fans need not be told, but for those of you in the dark, the prog rockers released a three part documentary titled The Spirit Carries On.  The docu-search for a drummer shows the 7 drummers DT trialed and tested before coming up with their final choice as the official new-Portnoy.  
You can view the video over at Roadrunner Record's YouTube Channel.