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Author: Didier Kryn
Date:  
To: dng@lists.dyne.org
Subject: Re: [DNG] What does Devuan expect from a boot-loader?
Le 01/10/2016 11:11, Rick Moen a écrit :
> Quoting Didier Kryn (kryn@???):
>
>> I'm not happy with Grub2 (I preferred Grub-legacy), but it works
>> with the default version of mdadm's superblock. According to the
>> doc, Lilo works with the old 0.90 mode only, because the superblock
>> is at the end of the partition and it doesn't see it.
> I'm sorry, but _where_ in the Boot+Root+Raid+LILO HOWTO does it say
> that? I see a couple of mentions of raidtools-0.90, but absolutely
> nothing that says lilo works with 'old 0.90 mode only'.


     In the last sentence of the following paragraph:


             ----------



    3.1 Booting RAID 1 with standard LILO


To make the boot information redundant and easy to maintain, set up a
small RAID1 and mount it on the */boot* directory of your system disk.
LILO does not know about device 0x9?? and can not find the information
at boot time because the raid sub system is not active then. As a simple
work around, you can pass LILO the geometry information of the drive(s)
and from that, LILO can determine the position of the information needed
to load the kernel even though it is on the RAID1 partition. This is
because the RAID1 partition is the same as a standard partition but with
a raid super-block written at the end.

             -----------


     This works with RAID1 and with superblock version 0.90 because, if 
you ignore the superblock at the end, the partitions look exactly like 
containing a bare filesystem (and are identical). It is only visible 
that these are part of a RAID1 if you can decode the superblock at the 
end. Any application knowing nothing of a RAID would work the same, 
reading only one disk.


     With newer versions, the superblock is at the beginning, so that 
the above doesn't apply.


     Didier