Dell MD1200 (6gb/s jbod enclosure) and 12 Gb/s drives
Drives with a 4K native sector size aren't supported by the MD1200.
http://downloads.dell.com/manuals/common/md1200_md1220_supportmatrix_en-us.pdf
- Drives with 12 Gbps interface speed will down-train to 6 Gbps when installed in the enclosure. The following are not supported on MD1200/MD1220 enclosures:
- 4Kn sector size
The ST4000NM0023 drives (Dell P/N 529FG) should work as expected, so if you can return or repurpose the ST4000NM0014 drives that would be a good place to start.
SAS is backward compatible...
Your 12G drives will downshift to 6G speed.
That is all.
But you're describing a different problem... and that's the displayed capacity of the disks.
You should upgrade firmware on all controllers and components.
I'm just guessing here but the drives you have are the 4k sector drives correct? The drives you need are the 512b sector size drives.
512b is x8 times smaller than 4k and the size you are seeing in BIOS is ~x8 times smaller than the actual drive size. It sounds like BIOS is calculating the drive size based off of only seeeing the first 512b of every 4k sector on the drive