[Bug 1019389] Re: Grub 2 hangs on boot after installing on RAID1 device (/dev/md0), reports no problems during install

Tue Jul 3 17:18:24 UTC 2012

Hi Philip,

I am attaching output from a test machine where grub2 was installed to
/dev/md0 and where booting hangs. The RAID1 array is "degraded" (with
only one member), to keep things simple.

Here is the output of mdadm --detail /dev/md0 on the same machine, so
you can see it is with metadata v1.0:

/dev/md0:
        Version : 1.0
  Creation Time : Fri Jun 29 17:39:34 2012
     Raid Level : raid1
     Array Size : 58615632 (55.90 GiB 60.02 GB)
  Used Dev Size : 58615632 (55.90 GiB 60.02 GB)
   Raid Devices : 2
  Total Devices : 1
    Persistence : Superblock is persistent

    Update Time : Tue Jul  3 17:15:03 2012
          State : clean, degraded 
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

           Name : test7:0  (local to host test7)
           UUID : 00c39b80:be939cc6:f55890ef:adcd3a36
         Events : 2678

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       0        0        1      removed

** Attachment added: "grub2_failing_array_started.txt"
   https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1019389/+attachment/3212315/+files/grub2_failing_array_started.txt

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https://bugs.launchpad.net/bugs/1019389

Title:
  Grub 2 hangs on boot after installing on RAID1 device (/dev/md0),
  reports no problems during install

Status in “grub2” package in Ubuntu:
  New

Bug description:
  This is 100% reproducible with metadata 0.9 and 1.0. We are installing
  a system with FAI (Fully Automatic Installation), and creating a full
  disk RAID1 array with two devices (/dev/sda and /dev/sdb). This
  results in a device /dev/md0 which we then label with a GPT label, and
  partition with parted, which gives us devices of the form /dev/md0p1,
  /dev/md0p2, etc.

  Since we are creating the RAID array with metadata 0.9 or 1.0, the
  metadata ends up at the end of the array, and so the BIOS should have
  no trouble reading from each disk individually to load the boot-
  loader, etc. What's more, grub2 supports GPT, and ordinarily has no
  trouble booting from a GPT labeled disk.

  At the end of the FAI installation, we install grub2 like this:

  grub-install /dev/md0

  which results in the usual "no errors reported" message that Grub2
  prints out. What we expect at this point is for md to automatically
  sync the grub2 changes to both /dev/sda and /dev/sdb, and for the BIOS
  to be able to boot from either device.

  What happens instead is that when the BIOS attempts to boot from
  either device, it hangs with a cursor blinking at the top-left corner
  of the screen *indefinitely*. So, it seems like although Grub 2 thinks
  the installation went fine, it is not actually OK.

  The interesting thing is that when we install Grub 2 to /dev/sda and
  /dev/sdb individually, rather than /dev/md0, everything works as
  intended. I've seen references on the web indicating that installing
  to the raw devices is the right thing to do, but I could not find any
  official documentation supporting the claims.

  If grub is supposed to be installed to /dev/sda and /dev/sdb, then the
  bug is that it doesn't complain when an attempt is made to install it
  to /dev/md0.

  If it should work even when installed to /dev/md0 (with metadata 0.9
  and 1.0), then the bug is that it doesn't actually install properly.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: grub2 1.99-21ubuntu3.1
  ProcVersionSignature: Ubuntu 3.2.0-25.40-generic 3.2.18
  Uname: Linux 3.2.0-25-generic i686
  ApportVersion: 2.0.1-0ubuntu8
  Architecture: i386
  Date: Fri Jun 29 15:21:36 2012
  ProcEnviron:
   TERM=xterm
   SHELL=/bin/bash
  SourcePackage: grub2
  UpgradeStatus: No upgrade log present (probably fresh install)

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