Have you checked that the SATA ports used belong to the same RAID controller? when several SATA ports are present, more than one RAID controller.
Please make sure each RAID is connected to a single RAID controller.
Also, I would like to get your system information.
Please run the Intel® System Identification Utility (Intel® SIU) and attach the report in your answer.
I look forward to your reply.
I ran the report as requested and attached the results.
I have also attached a shot of the total drive configuration from Win Disk Mgt Utility
And a shot of the Bios RAID setup
BTW: the report does not indicate it but this is an HP Z400
There are a number of interesting things here with the 3 reports....
Intel SIU Report
1) The report show a Total Storage Size of 6.8 TB (correct)
There are: (1) 3TB non RAID drive + (2) 450GB R1 SSD drives + (2) 4TB R1 Seagate drives, which adds up to 6.8 TB (after formatting)
2) BUT... The report identifies only 2 drives (not the correct configuration of all the drives)
Disk S: at 3.6 TB -> This is correct and is one of the two drive R1 pair that is being mis-reported (mentioned originally)
Disk E: at 1.1TB -> as you can see from the other attachment, E: is only 1 partition of a 3TB drive which is stand-alone (not RAID)
Missing is the Disk 1 at 447GB which is the drive Pair correctly being reported by Windows and RST as R1
Windows Disk Utility
the Windows disk util screen (top portion) indicates that S: is "Mirrored" so it seems to know something is going on...
RAID BIOS SETUP
Notice that this shows the 4TB disks on ports 4 and 5 as
(a) 1.678TB Not 4TB - curious, unless this older bios cannot cope with a 4TB drive..
(b) Non-RAID (initially set them up as R1)
I suppose this might explain why windows and RST do not show them as R1,
But obviously something was communicated to Windows since it knows that they are mirrored.
Maybe the Z400 cannot support dual R1 configurations?
So can I conclude that the 450GB pair is R1 in hardware, and the 4TB pair is being mirrored (R1) in software?
Hope this helps.
I was checking the user guide for this device, and I encountered with some information about RAID configurations.
Please refer to the page 7 of this file (check notes): http://www8.hp.com/h20195/v2/GetPDF.aspx/c04110960.pdf
I would recommend you to double check if 2TB+ RAIDs can be enabled in the system.