Bug#610202: grub fails to boot from degraded RAID5 array, "Error: file not found."

[Jesse Molina]

Package: grub
Severity: normal


Hi.  This might be a wishlist item since I don't know what the
official status is on raid5 support.  At the very least this is
an FYI to other users.

I wanted to test out the worthiness of raid5 support with grub
since I had heard that it had been added awhile back.

I tested with three 80GB SATA disks on the current netinst testing
installer image as of this date.  FYI, grub-installer was run
against /dev/sd[a-c] and /dev/md0, just to be sure.

raid5 booting works great under normal conditions.

However, when any one of the three disks is removed, the system
no longer boots. I did test the removal of all three induvidually.
Upon re-insertion of all three disks, the system boots normally.

Grub loads it's boot loader and then fails with "Error: file not found."
and gives a "grub recovery>" or similar prompt.

This would render a system unbootable, should any one of the drives fail
and perhaps it was not noticed by the sysadmin or a failure occurs during
normal cold-boot maintenance.

I don't know what the technical challenges are, but hopefully this can 
be fixed some day.  Being able to boot from a raid5 mdadm array is
really really cool.


-- System Information:
Debian Release: 6.0
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash