Bug#784070: mdadm Software RAID1 with GPT on Debian 8.0.0 amd64 - Does not mount/boot on disk removal

[Michael Tokarev]

11.06.2015 14:21, Robert.K. wrote:
> I apologize if I missed something, but ONLY adding rootdelay=XX guessed seconds does not help against being dropped to an initramfs-shell.
> 
> There may be two different bugs?
> 
> One for when not waiting for slow devices but the boot continues, which is cured by rootdelay=xx. This error/bug has the message "Found some drive for an array that is already active" and blinks by when booting. I guess this is #714155 ?

No.  This is something entirely different, and is specific to your setup.

> And another - much worser one - that halts the boot process and drops to an initramfs-shell where some of the md-devices are shown as RAID0 instead of RAID1 when doing mdadm --detail /dev/mdX

Here's your problem.  I've no idea how this happened, but you have a messed-up
configuration of your array(s) (hopefully just one).  This is neither #714155
nor #784070 and it is something which, unless there's a serious bug in mdadm,
should not happen at all.  As far as I understand, your raid1 somehow become
raid0, which is kind of impossible without manual intervention and/or messing
up with metadata.

Please note that your first email (to which I replied) in this thread was
really different, it shows successful result when adding rootwait.  Now you
say it doesn't work and your raid array has been converted to raid0.

If you need your particular problem to be resolved (if it is possible to
recover from that state) please collect all information (mdadm --detail,
mdadm --examine for all relevant devices, configuration which you expect
and configuration which you actually have, contents of mdadm.conf) and
post to linux-raid at vger.kernel.org asking for support.  When doing so,
please refrain from using phrases like "Adding bootdegraded=1 and such"
and "after forcing a boot etc" -- thsese are not helpful at all, there's
no action "such" and "etc", this might mean anything and we don't have
crystal ball to read your mind.

/mjt