Re: Raid5 regression

[Phillip Susi <psusi@cfl.rr.com>]

On 5/4/2011 7:23 AM, Goswin von Brederlow wrote:
> That is a problem mdadm has (had?) too. The problem arises when the
> alignment of the partition and its size causes the metadata of the
> partition to be also valid for the disk (as in the partition ends
> exactly at the end of the disk).
>
> One of the reasons not to use metadata at the end of the disk.

I thought that could be the problem so after speaking with Collin on IRC 
yesterday, I checked and the partition ends over 300 sectors before the 
end of the disk, which is enough to prevent the superblock in the 
partition from being mistaken for one on the end of the disk.

At least it should be, and it was under Maverick, but does not seem to 
be anymore in Natty.  Just to make sure there wasn't another actual 
superblock at the end of the disk, I zeroed out the sectors from the end 
of the partition to the end of the disk and it did not change anything.

It seems that somehow this new version of grub is now scanning more than 
just the last whole 64k of the disk, though looking at the code, I don't 
see how.