Asus RS100-E4/PI2 - Manual (Page 118)

6-20 Chapter 6: RAID Configuration
4. Select all the drives required for the RAID set, then press <Enter>. The
configurable array appears on screen.
5. Press <F10>, select the configurable array, then press <SpaceBar>.
The logical drive information appears including a Logical Drive menu
that allows you to change the logical drive parameters.