I have an NVidia ION board with 4 SATA ports and want to use that to run a Linux Server (CentOS 5.4). I first hooed up 3 HDs (that will be a RAID5 array) and a forth small boot HD.

I first started to use the onboard RAID capability but that does not work correctly under Linux: the raid capacity is not a real RAID but uses lvm to define some arays.

After setting the BIOS back to normal SATA mode and whiping the HDs, the first boot harddisk (/dev/sda) is seen as /dev/sda BEFORE mounting and after mounting as /dev/mapper/nvidia_. CentOS is unable to install on it (and grub is not installable on it either).

So somehow the harddisk is still seen as if it belongs to some lvm volume. I tried to clean out the HD by issuing a few dd if=/dev/zero of=/dev/sda commands to wipe the starting cylinders and final cylinders but to no avail.

Did anyone see this problem and did anyone find a solution?

UPDATE

When I create only a single ext3 partition on the first HD (/dev/mapper/nvidia_...) no LVM partitions are seen and I can boot from /dev/mapper/nvidia_.... Now the next step is to see how I can get rid of this folly.