Asus RS120-E4/PA2 - Manual (Page 119)

ASUS RS120-E4/PA2 6-13
6. Follow steps 6 to 7 of the Creating a RAID set: Using Easy Configuration
section.
7. Select Size from the Logical Drive menu, then press <Enter>.
8. Key-in the desired logical drive size, then press <Enter>.
9. Follow steps 8 to 13 of the Creating a RAID set: Using Easy Configuration
section to add the new RAID configuration.