[CentOS] HD/Partitions/RAID setup

[Matt Hyclak]

On Wed, Apr 11, 2007 at 11:32:22AM -0600, Ashley M. Kirchner enlightened us:
>    I have a machine that's been configured as follows using its BIOS tools:
> 
>    SATA-0 is a 160 GiB drive used as boot
>    SATA-1 and SATA-2 are both 500 GiB drives and were configured as a 
> RAID-1 in BIOS.
> 
>    When the system boots up, BIOS reports 1 160 GiB SATA drive, and 1 
> Logical volume as RAID-1 ID#0 500 GiB, which is what I would expect it 
> to report, as the two drives are now raided together.
> 
>    However, when I boot into the Centos installer and I get to 
> configuring the partitions, it lists both sda, sdb, and sdc as 
> available.  Both sdb and sdc are 500 GiB.  I would've expected to only 
> see one drive for the RAID setup.
> 
>    Can someone explain why I see both drives and how am I supposed to 
> configure them?  I thought if I configured the BIOS to raid them, I 
> wouldn't have to do anything in the OS other than to format the thing 
> and expect it to work.

You would be able to do that if you were using a real RAID card, but the
crap that comes on your motherboard is nothing more than a fancy hardware
interface to software drivers that do the RAID.

See http://en.wikipedia.org/wiki/FakeRAID for more details.

Your best bet is to either get a real hardware RAID card (3ware, etc.) or to
use the software RAID built into linux (md).

Matt

-- 
Matt Hyclak
Department of Mathematics 
Department of Social Work
Ohio University
(740) 593-1263