Hi guys,

I hope someone will help with this.

problem in short:
I cannot figure out why mdadm software raid fails to autodetect and assemble raid1 array members after every reboot.
Somehow it assembles raid members wrongly. After I fix it manually it works fine again until the next reboot. It seemed to work fine initially.

more details:
on boot mdadm assembly is wrong. what I get is
cat /proc/mdstat:
md9: active raid1 sdb1 sda0(which absolutely wrong - no idea how it ends up with this).
other members are not listed at all. Ubuntu fails to mount and boot stops with initramfs prompt.
then I have to manually do:
mdadm --stop /dev/md9
mdadm -A --scan
now it assembles all raid volumes correctly.
cat /proc/mdstat:
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md9 : active raid1 sda9[0] sdb9[1]
7378880 blocks [2/2] [UU]
md0 : active raid1 sda8[0] sdb8[1]
173521856 blocks [2/2] [UU]
md1 : active raid1 sda7[0] sdb7[1]
97659008 blocks [2/2] [UU]
md6 : active raid1 sda6[0] sdb6[1]
9767424 blocks [2/2] [UU]
md2 : active raid1 sda5[0] sdb5[1]
97659008 blocks [2/2] [UU]

then it boots and works fine till next reboot.

I am using
Ubuntu Lucid lynx with grub2.
Box is Dell XPS420 with 2 hard drives and fake raid controller. It had fake raid0 installed by default with windows but I disassembled and disabled that in BIOS and created Linux software raid basically from scratch using alternative Ubuntu install.

thanks for help,
agurkas

Did you make a mdadm.conf file with something like mdadm -D --scan >> /etc/mdadm/mdadm.conf ?

thanks for asking but yes I did. at the bottom of /etc/mdadm/mdadm.conf I have all members listed by UUID:
#taken from #mdadm --examine --scan
ARRAY /dev/md2 level=raid1 num-devices=2 UUID=c0612d2a:3ce4c7c9:3d186b3c:53958f34
ARRAY /dev/md6 level=raid1 num-devices=2 UUID=7ce4a26e:1ffb7c27:5611f15b:a92b01a9
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=6977edd0:1bc5a44e:5611f15b:a92b01a9
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=41ea4263:2d9ec7d3:21f2bbc1:ca3ddc1f
ARRAY /dev/md9 level=raid1 num-devices=2 UUID=383abd60:380d197a:5611f15b:a92b01a9

any ideas?
BTW.
all those raid partitions are also set to Linux raid autodetect as it should be. From fdisk I have output that I have noticed has sda8 partition end and sda9 partition start to be same cylinder number 59883 for some reason. Could this be a problem?

fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8ef2d872

Device Boot Start End Blocks Id System
/dev/sda1 * 1 12748 102396928 7 HPFS/NTFS
/dev/sda2 12749 60802 385988219+ 5 Extended
/dev/sda5 12749 24906 97659103+ fd Linux raid autodetect
/dev/sda6 24907 26122 9767488+ fd Linux raid autodetect
/dev/sda7 26123 38280 97659103+ fd Linux raid autodetect
/dev/sda8 38281 59883 173521920 fd Linux raid autodetect
/dev/sda9 59883 60802 7378944 fd Linux raid autodetect

Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8d1eaa59

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 12748 102396928 7 HPFS/NTFS
/dev/sdb2 12749 60802 385988219+ 5 Extended
/dev/sdb5 12749 24906 97659103+ fd Linux raid autodetect
/dev/sdb6 24907 26122 9767488+ fd Linux raid autodetect
/dev/sdb7 26123 38280 97659103+ fd Linux raid autodetect
/dev/sdb8 38281 59883 173521920 fd Linux raid autodetect
/dev/sdb9 59883 60802 7378944 fd Linux raid autodetect

Disk /dev/md2: 100.0 GB, 100002824192 bytes
2 heads, 4 sectors/track, 24414752 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md2 doesn't contain a valid partition table

Disk /dev/md6: 10.0 GB, 10001842176 bytes
2 heads, 4 sectors/track, 2441856 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md6 doesn't contain a valid partition table

Disk /dev/md1: 100.0 GB, 100002824192 bytes
2 heads, 4 sectors/track, 24414752 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md1 doesn't contain a valid partition table

Disk /dev/md0: 177.7 GB, 177686380544 bytes
2 heads, 4 sectors/track, 43380464 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md0 doesn't contain a valid partition table

Disk /dev/md9: 7555 MB, 7555973120 bytes
2 heads, 4 sectors/track, 1844720 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md9 doesn't contain a valid partition table

any ideas?

thanks

solved it myself.
I deleted raid member md9 (was not used anyway)
deleted partitions that were used in that raid.
/dev/sda9
/dev/sdb9
not sure if that makes any difference but I placed raid members in mdadm.conf in order by md number 0,1,2,6
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=41ea4263:2d9ec7d3:21f2bbc1:ca3ddc1f
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=6977edd0:1bc5a44e:5611f15b:a92b01a9
ARRAY /dev/md2 level=raid1 num-devices=2 UUID=c0612d2a:3ce4c7c9:3d186b3c:53958f34
ARRAY /dev/md6 level=raid1 num-devices=2 UUID=7ce4a26e:1ffb7c27:5611f15b:a92b01a9

now it boots with no problem at all.

regards

agurkas