[CentOS] Data corruption on external hard disk

Sat Aug 4 15:20:48 UTC 2007
Johnny Hughes <johnny at centos.org>

Niki Kovacs wrote:
> Daniel de Kok a écrit :
>> On Sat, 2007-08-04 at 07:09 +0200, Niki Kovacs wrote:
>>> [kikinovak at buzz:/media/disk/Films] $ ls -l
>>> total 692996
>>> -rw-r----- 1 678756852  34537972 148381783526817280 avr 28 01:01 Cinema
>>> drwxr-xr-x 3 kikinovak kikinovak               4096 mai  9 10:07 Anime
>>> drwxrwxrwx 4 kikinovak kikinovak               4096 mai 10 12:25 Series
>>>
>>> Notice that the file size is something like petabytes :oD
>>>
>>> Is there any way to repair this obviously corrupt data?
>>
>> Looks like a broken inode (or incorrect directory entry). I'd make a
>> backup image of the disk first (if that works without serious errors)
>> with dd. After that, run a badblocks check, and a fsck.
>>
> Argh. Looks like a complete data loss. Well, not complete. Fortunately I
> had most of it on another PC. I just lost all my films. (Gasp! David
> Lynch gone, Hitchcock gone, Cronenberg gone...)
> 
> Now I reformatted the HD with ext2, and badblocks is currently chugging
> away for the next few hours probably.
> 
> How do broken inodes happen? I'm a bit reluctant - for obvious reasons -
> to entrust data to that disk again. Can it be that overheating creates
> read/write errors, without actually corrupting the disk?

Normally, unplugging external drives without unmounting them is the
culprit on an external USB device.  Also, just powering off the drive
without unmount it if it is an externally powered drive.  On internally
mounted drives, usually turning off the system without shutting it down,
loss of a power supply and / or loss of power to a live system.

Sometimes a bad driver can cause problems for certain devices.

I would use an ext3 file system as it has a journal ... and journals can
recover data from the journal.

Thanks,
Johnny Hughes

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