Linux md RAID, bizarre md_d1 device

[Ellixis]

Hi all,

Here is my problem :
Each time I reboot, and I do cat /proc/mdstat, I got a /dev/md_d1 device with /dev/sdb3 as a spare drive.
But I've never created a /dev/md_d1, and altough I stop the raid and reset the superblock, it still re-appears after a reboot.

# mdadm --stop /dev/md_d1
mdadm: /dev/md_d1 stopped

# mdadm --zero-superblock /dev/sdb3

I've also tried the following after a reboot :

mdadm: set /dev/sdb3 faulty in /dev/md_d1
mdadm: hot remove failed for /dev/sdb3: Device or resource busy

It seems there is a rogue superblock somewhere on /dev/sdb3 that makes it detected as a RAID member on boot. How can I really reset this partition or drive ?

My system is :

Ubuntu 9.04
2 * 1TB Hard Drives (sda, sdb)
Partition layout on sda & sdb :

sda1: boot+system
sda2: swap
sda3: data

/dev/md1 (RAID1) : /dev/sda3, /dev/sdb3


More detail on partitions sda :

# sfdisk -l /dev/sda

Disque /dev/sda : 121601 cylindres, 255 têtes, 63 secteurs/piste
Unités= cylindres de 8225280 octets, blocs de 1024 octets, décompte à partir de 0

Périph Amor Début Fin #cyls #blocs Id Système
/dev/sda1 * 0+ 13054 13055- 104864256 83 Linux
/dev/sda2 13055 13303 249 2000092+ 82 Linux swap / Solaris
/dev/sda3 13304 121600 108297 869895652+ fd Linux raid autodetect
/dev/sda4 0 - 0 0 0 Vide

More details on raid :

# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md_d1 : inactive sdb3[1](S)
869895552 blocks

unused devices: <none>


# mdadm --query /dev/sdb3
/dev/sdb3: is not an md array
/dev/sdb3: device 1 in 2 device undetected raid1 /dev/md1. Use mdadm --examine for more detail.


# mdadm --examine /dev/sdb3
/dev/sdb3:
Magic : a92b4efc
Version : 00.90.00
UUID : 05b3734c:afb4771e:fd8bbc22:8698eb7e (local to host zhong)
Creation Time : Wed Aug 5 22:39:04 2009
Raid Level : raid1
Used Dev Size : 869895552 (829.60 GiB 890.77 GB)
Array Size : 869895552 (829.60 GiB 890.77 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1

Update Time : Fri Aug 7 05:24:06 2009
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : ab89198b - correct
Events : 69380


Number Major Minor RaidDevice State
this 1 8 19 1 active sync /dev/sdb3

0 0 8 3 0 active sync /dev/sda3
1 1 8 19 1 active sync /dev/sdb3


# mdadm --examine --scan
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=05b3734c:afb4771e:fd8bbc22:8698eb7e

I have created my /dev/md1 using this command :

# mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3

mdadm.conf :

# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#

# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
DEVICE partitions

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays

# This file was auto-generated on Thu, 19 Mar 2009 01:47:50 +0100
# by mkconf $Id$

[grantemsley]

Many people have had this issue, I believe after a kernel upgrade. Searching for md_d1 on the forum should find it.

I believe the solution is to regenerate mdadm.conf...it's missing the array settings.

[fjgaude]

Try doing this and then rebooting:


sudo mdadm --examine --scan --config=mdadm.conf >> /etc/mdadm/mdadm.conf

Let us know what happens. Thanks!

[Ellixis]

Try doing this and then rebooting:


sudo mdadm --examine --scan --config=mdadm.conf >> /etc/mdadm/mdadm.conf

Let us know what happens. Thanks!

It works now after rebooting, thanks ! It seems to be a bug since Jaunty, a shame :(

[fjgaude]

It's amazing how Ubuntu takes two steps forward and a half-step backward with each release, yes!

Glad you are up and running.