Booting from firmware RAID

ameiji wtf.jlaine at
Fri Mar 18 06:48:15 UTC 2011

On Wed,16-03-2011 [16:25:54], Ilya Kazakevich wrote:
> Thank you.
> I configured boot0 to my ar0 and tried to boot from it. It freezes.
> I use RAID10 and Intel-ICH7.
> Looks like I've faced with some other troubles..
> Ilya.
> On Wed, Mar 16, 2011 at 4:05 PM, mcoyles
> <mcoyles at>wrote:
> > >This is probably more PC-specific than freebsd-specific question. I have
> > >intel firmware raid. OS needs drivers to work with it. FreeBSD sees it as
> > >ar0, so it has drivers.
> > >But I want my OS to be installed on this drive and boot from it. It is not
> > >good idea, but I really want to do it:)
> > >Is it possible?
> > >
> > >boot0 and boot1 both work with HDD via BIOS interrupts and CHS, right? So,
> > >how do they know how to access RAID? They has no drivers.
> > >Or BIOS supports interrupts to access RAID with out of drivers? If so --
> > >what for drivers are needed? To access drive via ATA interface?
> >
> > Bios support interrupts and can thus boot from firmware raid.
> > Under windows drivers typically just give you full speed / management
> > features
> >
> > -----
> > Marci
> >
> >

Hi, here what man atacontrol says:

		  Although the ATA driver allows for creating an ATA RAID on
               disks with any controller, there are restrictions.  It is only
               possible to boot on an array if it is either located on a
               real RAID controller like the Promise or Highpoint controllers, 
		or if the RAID declared is of RAID1 or SPAN type; in
               case of a SPAN, the partition to boot must reside on the first
               disk in the SPAN.

Not sure if it's your case though.

	A complex system that works is invariably found to have
evolved from a simple system that works.

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