hi,Sir
May I know which OS types you installed. first you shoudl check the HPE OS matrix website to confirm this DL120G5 can support or not support the OS.
http://h17007.www1.hpe.com/us/en/enterprise/servers/supportmatrix/windows.aspx#.Wm_XA_kdgZR
second,if the OS recognized the two separate hard drive ,that means the OS have not recognized the raid controller.so you should insert the raid controller driver by manual when install the OS.
I am an HPE Employee.
