Folks please help - I am a newb with a major headache at hand (perfect storm situation).

I have a 3 1tb hdd on my ubuntu 11.04 configured as software raid 5. The data had been copied weekly onto another separate off the computer hard drive until that completely failed and was thrown away. A few days back we had a power outage and after rebooting my box wouldn't mount the raid. In my infinite wisdom I entered

mdadm --create -f...

command instead of

mdadm --assemble

and didn't notice the travesty that I had done until after. It started the array degraded and proceeded with building and syncing it which took ~10 hours. After I was back I saw that that the array is successfully up and running but the raid is not

I mean the individual drives are partitioned (partition type f8 ) but the md0 device is not. Realizing in horror what I have done I am trying to find some solutions. I just pray that --create didn't overwrite entire content of the hard driver.

Could someone PLEASE help me out with this - the data that's on the drive is very important and unique ~10 years of photos, docs, etc.

Is it possible that by specifying the participating hard drives in wrong order can make mdadm overwrite them? when I do

mdadm --examine --scan 

I get something like ARRAY /dev/md/0 metadata=1.2 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b name=<hostname>:0

Interestingly enough name used to be 'raid' and not the host hame with :0 appended.

Here is the 'sanitized' config entries:

DEVICE /dev/sdf1 /dev/sde1 /dev/sdd1

CREATE owner=root group=disk mode=0660 auto=yes

HOMEHOST <system>

MAILADDR root


ARRAY /dev/md0 metadata=1.2 name=tanserv:0 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b


Here is the output from mdstat

cat /proc/mdstat 
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid5 sdd1[0] sdf1[3] sde1[1]
1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>


fdisk shows the following:

fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 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: 0x000bf62e

Device Boot Start End Blocks Id System
/dev/sda1 * 1 9443 75846656 83 Linux
/dev/sda2 9443 9730 2301953 5 Extended
/dev/sda5 9443 9730 2301952 82 Linux swap / Solaris

Disk /dev/sdb: 750.2 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 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: 0x000de8dd

Device Boot Start End Blocks Id System
/dev/sdb1 1 91201 732572001 8e Linux LVM

Disk /dev/sdc: 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: 0x00056a17

Device Boot Start End Blocks Id System
/dev/sdc1 1 60801 488384001 8e Linux LVM

Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0x000ca948

Device Boot Start End Blocks Id System
/dev/sdd1 1 121601 976760001 fd Linux raid autodetect

Disk /dev/dm-0: 1250.3 GB, 1250254913536 bytes
255 heads, 63 sectors/track, 152001 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: 0x00000000

Disk /dev/dm-0 doesn't contain a valid partition table

Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0x93a66687

Device Boot Start End Blocks Id System
/dev/sde1 1 121601 976760001 fd Linux raid autodetect

Disk /dev/sdf: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 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: 0xe6edc059

Device Boot Start End Blocks Id System
/dev/sdf1 1 121601 976760001 fd Linux raid autodetect

Disk /dev/md0: 2000.4 GB, 2000401989632 bytes
2 heads, 4 sectors/track, 488379392 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 1048576 bytes
Disk identifier: 0x00000000

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

Per suggestions I did clean up the superblocks and re-created the array with --assume-clean option but with no luck at all.

Is there any tool that will help me to revive at least some of the data? Can someone tell me what and how the mdadm --create does when syncs to destroy the data so I can write a tool to un-do whatever was done?

After the re-creating of the raid I run fsck.ext4 /dev/md0 and here is the output

root@tanserv:/etc/mdadm# fsck.ext4 /dev/md0 e2fsck 1.41.14 (22-Dec-2010) fsck.ext4: Superblock invalid, trying backup blocks... fsck.ext4: Bad magic number in super-block while trying to open /dev/md0

The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193

---

Per Shanes' suggestion I tried

root@tanserv:/home/mushegh# mkfs.ext4 -n /dev/md0
mke2fs 1.41.14 (22-Dec-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=128 blocks, Stripe width=256 blocks
122101760 inodes, 488379392 blocks
24418969 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
14905 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
    4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 
    102400000, 214990848

and run fsck.ext4 with every backup block but all returned the following:

root@tanserv:/home/mushegh# fsck.ext4 -b 214990848 /dev/md0
e2fsck 1.41.14 (22-Dec-2010)
fsck.ext4: Invalid argument while trying to open /dev/md0

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

Any suggestions?

Regards!