RAID 0 is ideal for non-critical storage of data that have to be read/written at a high speed, such as on an image retouching or video editing station.
Data are stored twice by writing them to both the data drive (or set of data drives) and a mirror drive (or set of drives). If a drive fails, the controller uses either the data drive or the mirror drive for data recovery and continuous operation. You need at least 2 drives for a RAID 1 array.
Format all disk.
From the first disk put 1Gb in /boot
leave unformatted the same number of GB on each partition and press create software RAID (md)
Select the “Create software RAID (“MD”)” button to open the creation dialog. The server installer supports creating devices with RAID levels 0, 1→ select all disk → press create.
From md0 free space create the partitions ass needed or required.