How to put win2012 x64 or 2008r2 x64 on RAID1 4tb?

Question

RAID

Good day. 2 days I fight with raid.
There is a supermicro server based on such a motherboard: https://goo.gl/FPYDFR
There are 2 hdds of 4TB each.
There are 2 Windows from the header.
Task: 1. divide RAID1 into 250GB (under the system) + everything else under the file trash.
2. Put Windows on this 250GB partition.
What I do:
Create raid1, boot into windows installation, diskpart->select disk 0
convert gpt
create partition primary size=256000
create partition primary #to everything else
Error - windows cannot be installed to a GPT partition.
Or
diskpart->select disk 0
convert gpt
I put any Windows, and already I can’t see more than 2TB in it, because. the disk partition is not dynamic, but I can not convert.
And another small question - is there a comparison of ntfs rights for 2008r2 and 2012r2 somewhere on the net?
Thank you.

Answer 1

Booting from GPT requires UEFI support in the motherboard. This motherboard does not have it.

Answer 2

And if you take the driver for the raid and slip it to Windows at the time of installation?
Or mark the system disk in mbr?