Messages in this thread |  | | Date | Tue, 8 Jan 2002 20:26:11 -0700 | From | Richard Gooch <> | Subject | Re: fs corruption recovery? |
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Andreas Dilger writes: > On Jan 08, 2002 21:52 -0500, Kervin Pierre wrote: > > I install and used 2.4.17 for about a week before my filesystem > > corrupted. I've tried 'fsck -a' but it complains that there was no > > valid superblock found. > > Try "e2fsck -B 4096 -b 32768 <device>" instead. > > > Are there any tools or techniques that will recover data from the > > corrupted filesystem even if there isn't a valid superblock? Or is > > there a way to write a temporary superblock so I can access the > > information on the disk? > > The ext2 format (includes ext3) has backup superblocks for just this reason. > > > Lastly, if all else fails I'm going to try sending the drive one of > > those 'file recovery companies'. Does anyone have a recommendation for > > a particular company? I'm guessing that there'll be a few that wouldn't > > know what to do with a ext3 partition. > > Is the data really that valuable, and you don't have a backup? It may > cost you several thousand dollars to do a recovery from such a company. > Yet, it isn't worth doing backups, it appears.
And these companies don't really do much that you can't do yourself. I had a failing drive some years ago, where some sectors couldn't be read. So I tried to dd the raw device to a file elsewhere. Of course, dd will quit when it has an I/O error. So I wrote a recovery utility that writes a zero sector if reading the input sector gives an I/O error. Unfortunately, I couldn't mount the file (too much corruption), but I was able to use debugfs on it. I got the most important data back.
While I was waiting for 48 hours for the data to be pulled off (each time a bad sector was encountered, the drive would retry several times, with lots of clicking and rattling), I contacted one of these recovery companies. I wanted to know if they could recover the bad sectors. I was told no. After some probing, it turns out that all they do is basically what I was doing. They just charge $2000 for it.
No doubt if you took your drive to your local CIA/KGB/MI6 offices, they could recover some of those bad sectors. But I hear they charge their customers quite a lot...
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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