Re: Setting up fakeraid with mdadm / dmraid

[Jes Sorensen <Jes.Sorensen@redhat.com>]

"Christoph Pleger" <Christoph.Pleger@cs.tu-dortmund.de> writes:
> Hello,
>
> I have a machine with an LSI Megaraid Sofware RAID fakeraid, which uses
> ddf format. About two weeks ago, when I wanted to install the machine, I
> configured a RAID 1 array in the BIOS config utility and then booted the
> machine from PXE with an NFSROOT. mdadm and dmraid are installed in the
> NFSROOT, dracut is used for initrd generation. As dracut prefers mdadm
> over dmraid, mdadm was chosen for RAID management.
>
> But though mdadm detected the RAID (it created container device /dev/md127
> and raid device /dev/md126), it destroyed it - that is, though I did not
> perform any action on the raid disks, at the next boot, the BIOS RAID
> utility had "forgotten" about the RAID configuration it had created
> before.
>
> Why are the possible reasons for that?

The LSI uses DDF and requires mdmon etc. to be launched. It is not clear
from your posting what you created, but you would have to update dracut
to include mdmon etc. after creating the RAID.

Jes