RAID 5 array bug without an interesting name

Bug #689600 reported by Delan Azabani on 2010-12-13
20
This bug affects 1 person
Affects Status Importance Assigned to Milestone
udev (Ubuntu)
Undecided
Unassigned

Bug Description

I have created a RAID 5 array, md0, using mdadm including three whole disks, sdb, sdc and sdd, like this:

mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb /dev/sdc /dev/sdd

The RAID array works just fine and automounting using /etc/fstab works fine too. There is a bug with how some applications like palimpsest recognise the member drives, which disappears when the array is restarted.

Upon booting, and having the array autostarted:

- sdb is a 'RAID Component' (this is correct)
- sdc and sdd are both:
----- 1.0TB capacity at the top
----- 2.0TB capacity at the bottom
----- with a 1.0TB ext4 partition 'raid'
----- '18446743 TB (-1,000,204,443,648 bytes)' free space at the end
- the 'Places' menu has two unmountable volumes 'raid' which are presumably sdc and sdd

Weird?

When restarting the array (unmount, stop array, start array):

- sdb, sdc and sdd are all 'RAID Component' disks (this is correct)
- the 'Places' menu does not have any single disks' entries (this is correct)

Pictures:

http://i.imgur.com/Szh54.png -- palimpsest md0
http://i.imgur.com/mdxAz.png -- before restarting array, palimpsest on sdb (correct)
http://i.imgur.com/xQwb9.png -- before restarting array, palimpsest on sdc (bad behaviour)
http://i.imgur.com/cYALj.png -- before restarting array, palimpsest on sdd (bad behaviour)
http://i.imgur.com/oI8nA.png -- after restarting array, palimpsest on sdb (correct)
http://i.imgur.com/J35HF.png -- after restarting array, palimpsest on sdc (correct)
http://i.imgur.com/U0cAy.png -- after restarting array, palimpsest on sdd (correct)

Delan Azabani (azabani) on 2010-12-13
description: updated
affects: ubuntu → udev (Ubuntu)
Delan Azabani (azabani) wrote :

This only occurs when using whole-disk RAID members, but not when using partition members. Obviously, the former is more problematic, just like whole-disk file systems, confusing programs that expect partitions.

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