Re: Linux RAID metadata format docs?

[Jeff Garzik <jgarzik@pobox.com>]

On Fri, Nov 14, 2003 at 09:31:14PM +0200, Matti Aarnio wrote:
> On Fri, Nov 14, 2003 at 01:50:13PM -0500, Jeff Garzik wrote:
> > Do any docs exist, that describe the on-disk md format?
> 
> Not as such.   An  H-file  isn't a document in itself...
> 
> > I'm talking with a vendor that would like to support booting off of 
> > "Linux RAID" (as they call it), from their card's BIOS, which implies
> > the vendor would need to add support for the md format to their BIOS.
> > 
> > 	Jeff
> 
> Problem there is the multitude of partition schemes, and that RAID
> superblocks are inside the partitions...

Yep.  Thought I consider it fairly pointless to support anything but
ms-dos partitions and EFI partitions.  Given limited development
resources, I don't see a huge need for (for example) BSD disklabel
support.


> Nevertheless I would love to be able to boot from _any_ of disks
> in a bootable RAID1 diskset.  I have just experimented with Highpoint's
> RocketRaid 1520, which almost can do that.  It fails if the primary
> disk is offline, but succeeds if secondary is out.
> I also liked their superblock location - very early in disk.
> Negative thing in the HPT BIOS is, that if it detects a fault, it
> wants user input instead of just trying starting disks a bit more 
> persistently, and continuing _soon_ the boot in degraded RAID1 mode
> without any user input.

Yeah, the main point is to be able to root in degraded mode, as well
as regular mode.

	Jeff