Just finished putting together a new server with four 1 TB hard drives in a RAID 5 and I had some fun getting Windows to install on them.
The total storage from the four drives worked out to be roughly 2.75 GB and I wanted three partitions (OS and two data partitions). Since the MBR partition scheme doesn't support anything over 2 TB I figured Windows would be smart enough to allow me to use a GPT and that would be that. Unfortunately things didn't quite work out that easy, Windows setup doesn't appear to be able to create partitions using GPT and the only solutions I seemed to be able to find involved creating an MBR partition then installing Windows and switching everything over to GPT.
That seemed like quite the ugly hack so I ended up using the RAID controller to create three virtual drives which could then be partitioned using the traditional MBR scheme. I guess I'll have to wait for Windows Server 8 for Microsoft to get this right.
Now that I had my three virtual drives I figured things were bound to work. I then ran into another issue, "Setup was unable to create a new system partition or locate an existing system partition. See the Setup log files for more information."
Thankfully Google was my friend for this one, apparently if you're using a USB stick for RAID drivers it must not be inserted before Windows asks for it and it needs to be removed right after the RAID drivers are installed. Sure enough leaving the USB stick out until setup asked for more drivers and then removing it once I got to the choose an install option did the trick. Windows is installing right now so I'll keep this updated if I have any more problems.
Thanks to [still compiling] for the article that pointed me in the right direction.