need some help very strange behavior mdadm writes data to non raid disk?

[Jelle de Jong <jelledejong@powercraft.nl>]

[-- Attachment #1: Type: text/plain, Size: 916 bytes --]

This message contains the following attachment(s):
debug-mdadm.txt
setup-mdadm.txt

Hello everybody

Thank you for supporting mdadm. I am creating my first raid1 array and 
got some very confusing issues.

My raid1 md0 array should consist out of disks:
/dev/sda1
/dev/sdb1

These are 749GB ext3 partitions in mirroring mode.

However when I reboot my system, mdadm tells me everything is fine and
is correctly using sda1 and sdb1.

But it is not using a 749GB partition, it is using the same partition
size as my /dev/sdc1 disk and when I write a test file to the root dir 
and then mount /dev/sdc1 the file is there also. So md0 is directly 
connected with /dev/sdc1. It does not make any sens to me.

Can somebody please look at my debug en setup file that i created and 
maybe see something that is going wrong?

Thanks in advance,

Jelle de Jong

ps. I am mailing this address directly please cc me in a reply


[-- Attachment #2: setup-mdadm.txt --]
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apt-get install mdadm

# step 1: setup partitions sizes on the first disk
parted /dev/sda
mklabel msdos
mkpart primary 0 749GB
mkpart primary 749GB 750GB
toggle 1 boot
print
quit

# step 2: copy partition table from sda to sdb
sfdisk -d /dev/sda | sfdisk /dev/sdb

# step 3: create raid mirroring setup
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1
mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sda2 /dev/sdb2

# step 4: create file systems on the first disk partitions
mkfs.ext3 /dev/md0
mkswap /dev/md1

# step 5: create the mdadm configuration file
mdadm --detail --scan --verbose > /etc/mdadm.conf
mdadm --detail --scan --verbose > /etc/mdadm/mdadm.conf

# step 6: watch how the reconstruction of the array's
watch cat /proc/mdstat

# step 7: change fstab
cat > /etc/fstab << "EOF"
UUID=10a11e44-a958-4d14-ae56-adf9af7c5c28 /               reiserfs notail       0       1
UUID=89162427-3092-48af-93f0-9123a4e031ea none            swap    sw       0       0
/dev/md0     /media/disk ext3       defaults            0       1
/dev/md1     none        swap       sw                  0       0
proc         /proc       proc       defaults            0       0
EOF

# step 8: create mount directory and mount disks
mkdir /media/disk
mount -a
touch /media/disk/test.txt
ls -hal /media/disk

# step 8: reboot the system and check raid disk are mounted
shutdown -r now
ls -hal /media/disk

# step 9: change to runlevel 1 to prepare for copying
init 1

# step 9: copy root directory
rsync -aqxP / /media/disk
# cp -ax / /mnt/newroot

# step 10: setup boot flags on disk
parted /dev/sdc
toggle 1 boot
print
quit

# step 11: change fstab
cat > /etc/fstab << "EOF"
/dev/md0     /           ext3       defaults            0       1
/dev/md1     none        swap       sw                  0       0
proc         /proc       proc       defaults            0       0
EOF

# step 12: reboot the system
shutdown -r now

-- -- -- --

# notes:
tune2fs -j
sfdisk -d /dev/sdb > partitions.sdb
sfdisk /dev/sdb < partitions.sdb

mdadm -S /dev/md0
mdadm -S /dev/md1
mdadm -S /dev/md2

mdadm /dev/md0 --fail /dev/sda1 --remove /dev/sda1
mdadm /dev/md1 --fail /dev/sda2 --remove /dev/sda2
mdadm /dev/md2 --fail /dev/sda3 --remove /dev/sda3

mdadm /dev/md0 --fail /dev/sdb1 --remove /dev/sdb1
mdadm /dev/md1 --fail /dev/sdb2 --remove /dev/sdb2
mdadm /dev/md2 --fail /dev/sdb3 --remove /dev/sdb3

[-- Attachment #3: debug-mdadm.txt --]
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touch /testfile-a.txt

ls -hal /testfile-a.txt
-rw------- 1 root root 0 2008-06-15 11:10 /testfile-a.txt

mount /dev/sda1 /media/sda1/
mount: unknown filesystem type 'linux_raid_member'

mount /dev/sdb1 /media/sdb1/
mount: unknown filesystem type 'linux_raid_member'

mount /dev/sdc1 /media/sdc1/

ls -hal /media/sdc1/testfile-a.txt
-rw------- 1 root root 0 2008-06-15 11:10 /media/sdc1/testfile-a.txt

-- -- -- -- --

df -hal
Filesystem            Size  Used Avail Use% Mounted on
/dev/md0              296G  284G   12G  97% /
/dev/sdc1             296G  284G   12G  97% /media/sdc1

df -halT
Filesystem    Type    Size  Used Avail Use% Mounted on
/dev/md0      ext3    296G  284G   12G  97% /
/dev/sdc1 reiserfs    296G  284G   12G  97% /media/sdc1


-- -- -- -- --

cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sda1[0] sdb1[1]
      731447360 blocks [2/2] [UU]

md1 : active raid1 sda2[0] sdb2[1]
      1124480 blocks [2/2] [UU]

unused devices: <none>

-- -- -- -- --

cat /etc/fstab
/dev/md0     /           ext3       defaults            0       1
/dev/md1     none        swap       sw                  0       0
proc         /proc       proc       defaults            0       0

-- -- -- -- --

cat /etc/mdadm/mdadm.conf
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=a8df884e:703cf3bc:109b2f78:2d361e62
   devices=/dev/sda2,/dev/sdb2
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=da5e027a:506d3587:109b2f78:2d361e62
   devices=/dev/sda1,/dev/sdb1

-- -- -- -- --

fdisk -l

Disk /dev/sda: 750.1 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00010329

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       91061   731447451   83  Linux
/dev/sda2           91062       91201     1124550   83  Linux

Disk /dev/sdb: 750.1 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00010329

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1       91061   731447451   83  Linux
/dev/sdb2           91062       91201     1124550   83  Linux

Disk /dev/md1: 1151 MB, 1151467520 bytes
2 heads, 4 sectors/track, 281120 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0xe8eb5d88

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

Disk /dev/md0: 749.0 GB, 749002096640 bytes
2 heads, 4 sectors/track, 182861840 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Disk identifier: 0x00000000

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

Disk /dev/sdc: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0004e3f2

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1       38562   309749233+  83  Linux
/dev/sdc2           38563       38913     2819407+  82  Linux swap / Solaris

-- -- -- -- --