Software raid broken in recent kernels

[Bruno Wolff III]

On Tue, Mar 11, 2008 at 14:40:30 -0400,
  Dave Jones <davej at redhat.com> wrote:
> On Tue, Mar 11, 2008 at 07:32:20PM +0100, Dennis Jacobfeuerborn wrote:
>  > I can't get recent kernels to boot because they don't seem to find 
>  > necessary devices ("no devices found for /dev/mdX"). The status is as follows:
>  > 
>  > works -> kernel-2.6.25-0.87.rc3.git4.fc9
>  > fails -> kernel-2.6.25-0.101.rc4.git3.fc9
>  > fails -> kernel-2.6.25-0.105.rc5.fc9
>  > 
>  > I checked bugzilla but couldn't find any relevant kernel bugs. Should I 
>  > file one or is this already known?
> 
> I don't recall anything in md changing recently that could explain this.
> I'm more inclined to believe it's another mkinitrd bug.
> Could you pull apart the working/broken initrds and compare them to see
> if there's something obviously different?

You might take a look at 435228. I have been having success with software
raid (1). I have been having troubles with encryption over software raid.
Make sure your mkinitrd is up to date. There have been occasional bad
versions but the latest (6.0.34) should work for software raid without
encryption.