LG NAS N1T3 logical disk errors

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frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

LG NAS N1T3 logical disk errors

Post by frankys12 » Wed Mar 13, 2013 3:37 pm

Hi All,

I have made the standard schoolboy error I did not back up my NAS device. The other day the device needed a reset and failed to reload.

I Spoke to LG and raise a support case, I had a prompt replay saying they need to take the device away.

I had a few email conversations with LG support whilst my devices was away where I stated if they need to wipe my data or replace the drive I would rather have the device back without any repair.

They told me the NAS has logical disk errors and returned without fixing.

I have now removed the disk and attached to an old Dell workstation and booted via PartedMagic (Linux) to copy my data off. However the drive appears as 4 drives that are un mountable - LinuxRAID, ext4 . I have tried mdadm and mount but I still can't mount the drive.

Can anybody advise me on how to get my data off, or am I data less :(

Any advise would be appreciated.

Many thanks

Franky

Mijzelf
Posts: 6207
Joined: Mon Jun 16, 2008 10:45 am

Re: LG NAS N1T3 logical disk errors

Post by Mijzelf » Wed Mar 13, 2013 7:19 pm

"Logical disk errors"? I don't see how that can exist. Anyway, can you provide some extra information? How many disks does the NAS have, and how were they arranged? (raid level, ...)
In Linux, what is the output of:

Code: Select all

fdisk -l
cat /proc/partitions
blkid

frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

Re: LG NAS N1T3 logical disk errors

Post by frankys12 » Thu Mar 14, 2013 10:07 am

Hi

The NAS had 1 disk (which is now attached to my pc) Here is a bit more info as requested.

fdisk -l

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Device Boot Start End Blocks Id System
/dev/sda1 1 1953525167 976762583+ ee GPT

Disk /dev/md2: 968.2 GB, 968202510336 bytes
2 heads, 4 sectors/track, 236377566 cylinders, total 1891020528 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


root@partedmagic:~# cat /proc/partitions
major minor #blocks name

7 0 61728 loop0
7 1 231076 loop1
11 0 315392 sr0
8 0 976762584 sda
8 1 22460416 sda1
8 2 7813120 sda2
8 3 945511424 sda3
9 2 945510264 md2

blkid
/dev/md2: UUID="b216b697-c280-4380-bd8e-13ac244f34c8" TYPE="ext4"
/dev/sda1: UUID="3c4838ed-6a37-2739-8876-bae7732855c4" TYPE="linux_raid_member"
/dev/sda2: UUID="f28474ea-d533-5833-8876-bae7732855c4" TYPE="linux_raid_member"
/dev/sda3: UUID="e00a1c6b-8128-96f7-617a-cb142c19fa68" UUID_SUB="c3165599-95c2-ca87-5592-e4961a0e9233" LABEL="LG-NAS:2" TYPE="linux_raid_member"
/dev/loop0: TYPE="squashfs"
/dev/loop1: TYPE="squashfs"

Mijzelf
Posts: 6207
Joined: Mon Jun 16, 2008 10:45 am

Re: LG NAS N1T3 logical disk errors

Post by Mijzelf » Thu Mar 14, 2013 1:52 pm

OK. So obviously the data is in a raidarray md2, which is located in partition sda3

What happens if you just try to mount /dev/md2?

Code: Select all

mkdir /tmp/mountpoint
mount -o ro /dev/md2 /tmp/mountpoint

frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

Re: LG NAS N1T3 logical disk errors

Post by frankys12 » Thu Mar 14, 2013 2:02 pm

HI Mijzelf,

I get this:

root@partedmagic:~# mkdir /tmp/mountpoint
root@partedmagic:~# mount -o ro /dev/md2 /tmp/mountpoint
mount: wrong fs type, bad option, bad superblock on /dev/md2,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
thanks

Mijzelf
Posts: 6207
Joined: Mon Jun 16, 2008 10:45 am

Re: LG NAS N1T3 logical disk errors

Post by Mijzelf » Thu Mar 14, 2013 3:35 pm

And? What does

Code: Select all

dmesg | tail
say, directly after an attempt to mount?

frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

Re: LG NAS N1T3 logical disk errors

Post by frankys12 » Fri Mar 15, 2013 7:46 am

Hi,

These are the results I get

dmesg | tail
[15188.401833] FAT-fs (sdb1): Directory bread(block 30668) failed
[15188.401840] FAT-fs (sdb1): Directory bread(block 30669) failed
[15188.401847] FAT-fs (sdb1): Directory bread(block 30670) failed
[15188.401854] FAT-fs (sdb1): Directory bread(block 30671) failed
[15188.401860] FAT-fs (sdb1): Directory bread(block 30672) failed
[15188.401867] FAT-fs (sdb1): Directory bread(block 30673) failed
[15220.091492] usb 1-8: USB disconnect, device number 9
[16306.953486] EXT4-fs (md2): bad block size 65536
[78501.606942] EXT4-fs (md2): bad block size 65536
[78543.377274] EXT4-fs (md2): bad block size 65536

Thanks

Mijzelf
Posts: 6207
Joined: Mon Jun 16, 2008 10:45 am

Re: LG NAS N1T3 logical disk errors

Post by Mijzelf » Fri Mar 15, 2013 9:46 am

[78543.377274] EXT4-fs (md2): bad block size 65536
Right. What is your kernel version (uname -a)? Until kernel 3.2 the blocksize of ext4 was limited to the page size of the memory, which is 4k on a x86/amd64 system. (But 64k is supported on many other platforms, ppc, mips, and, apparently, arm.) So I suppose your kernel is older.

As far as I can see you have 4 choices now:
  • Use debugfs.

    Code: Select all

    debugfs
     open -b 65536 /dev/md2
    ls
    cd /part/to/data
    rdump "MyData" /path/to/mounted/2nd_disk
  • Find a distro with a kernel >= 3.2
  • Connect the disk to another platform. If you can boot your LG using another disk, connect this one via sata/usb, and have a shell that could do. An old pre-x86 Apple running a modern Linux distro could do.
  • Use a low-level file recovery program like PhotoRec. Success depends on the nature of your data, and the amount of fragmentation. You might loose your metadata (filename, path, timestamp, ...)

frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

Re: LG NAS N1T3 logical disk errors

Post by frankys12 » Fri Mar 15, 2013 10:23 am

Thanks for this I appreciate all your help

One quick question I am attempting the debug method and I can see my data but I am having an issue with the last part trying to copy the data off

I have an external disk which is mounted as dev/sdc1 and I have created a directory called data

I get the following error message


debugfs: rdump "Family" /dev/sdc1
rdump: /dev/sdc1 is not a directory
debugfs: rdump "Family" /dev/sdc1/data
rdump: Not a directory while statting /dev/sdc1/data

any advice?

Mijzelf
Posts: 6207
Joined: Mon Jun 16, 2008 10:45 am

Re: LG NAS N1T3 logical disk errors

Post by Mijzelf » Fri Mar 15, 2013 10:32 am

/dev/sdc1 is not the mountpoint, it's the device node. When you execute 'mount' without params, the mountpoint is the directory next to /dev/sdc1.

frankys12
Posts: 6
Joined: Wed Mar 13, 2013 3:24 pm

Re: LG NAS N1T3 logical disk errors

Post by frankys12 » Fri Mar 15, 2013 12:18 pm

Hi Mijzelf

It worked!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thank you

You are a star :) :) :)

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