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

[Iordan Iordanov]

Public bug reported:

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)

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 precise

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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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