We have brand new PowerEdge 2970 server with two SAS drives in RAID1 array. We're trying to add third SATA drive and for some reason, the RAID controller continues to make the SATA drive the primary drive (/dev/sda).  I've looked through the RAID controller BIOS, even attempted to make a RAID1 array between two 1.5TB drives to see if more options would show up, however that doesn't seem to be the case.

I hope that there is somebody in this forum,  who is familiar with Dell products and can help me. Thank you.