Check your /etc/default/grub, if you use raid 1.

[Bruno Wolff III]

On Sun, Jul 29, 2012 at 10:42:26 -0400,
   Sam Varshavchik <mrsam at courier-mta.com> wrote:
>
>All I know is in F16 I discovered that a raid 1 volume whose uuid 
>does not get enumerated in the rd.md.uuid kernel boot parameters will 
>come up with one drive not in the array, maybe 5% of the time. I 
>wasn't the only one affected, there was another list member that 
>reported the same bug, and that putting the uuid back into grub.cfg 
>and /etc/default/grub fixed it.

>That, I think is a bug. Failing a drive should zero its superblock, 
>to force a real resync if it gets added back to the array.

Do you know if there are bug tracker entries for either of these bugs?

I'm interesting in following them.