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

[Lukasz T.]

On Thu, 11 Jun 2015 20:07:09 +0200 "Robert.K." <dotpointer at gmail.com> wrote:
> On Thu, 11 Jun 2015 20:20:23 +0300 Michael Tokarev <mjt at tls.msk.ru> wrote:
> > 11.06.2015 20:13, Robert.K. wrote:
> >
> > > The bug in this report (#784070) is about being dropped to a shell
when
> there are missing disks in a software RAID1 configuration upon boot.
> >
> > Ok, this makes sense.
> >
> > It is not RAID1 it is any RAID level, and it has nothing to do with GPT.
> >
> > /mjt
> >
> >
>
> I agree that it may be related to any RAID level. For me it was only
> related to RAID1 as I have only tried RAID1 configurations.
>
> I have not mentioned GPT for what I know.
>
> I am sorry if I have made you upset, I was only trying to help both the
> development and other people hitting the bug.
>
> Good luck if you try to solve it and try to work with the d-i team (debian
> installer?) again, you seem to know what you are doing.
>
> r

I think the problem is in file
/usr/share/initramfs-tools/scripts/local-top/mdadm on line 79
(mdadm-3.3.2-5-amd64).
The solution is replace line 79:

log_failure_msg "failed to assemble all arrays."

by:

log_warning_msg "failed to assemble all arrays...attempting individual starts"
for dev in $(cat /proc/mdstat | grep md | cut -d ' ' -f 1); do
    log_begin_msg "attempting mdadm --run $dev"
    if $MDADM --run $dev; then
      verbose && log_success_msg "started $dev"
    else
      log_failure_msg "failed to start $dev"
    fi
done

And that works. Founded and tested on polish debian forum.