Re: md extension to support booting from raid whole disks.

["H. Peter Anvin" <hpa@zytor.com>]

Daniel Reurich wrote:
>>>  
>> Grub is capable of doing that IF THE FIRMWARE CAN REACH IT.
> 
> Well if the firmware can't find one if the disks, then it doesn't matter
> what scheme we have.  Even a single disk won't work.

It is *quite* common that firmware can reach a subset of the disks.  If
not when the system is set up, then when a controller is blown and the
user has to install a new one.  I have seen this particular malfunction
up close more times than I can count.

> What's your beef. MD already reserve some space for the superblock, and
> write-intent bitmap (which I believe is also replicated across the
> member disks), so why not add some space to this to make it possible for
> a bootloader as well.

My beef is that you're actively promoting an extremely dangerous
concept, dangerous exactly because it is seductive -- "it seems so
easy."  Most users, you included, apparently, typically will have no
notion of the failure modes, and will pick the "easy" option.

Booting is ugly business.  I have dealt with the subtleties for almost
two decades, and it riles me when people go and foist off bad ideas on
users.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.