[TriLUG] data recovery - a modest how-to

[Jon Carnes]

This would be a great article to go up on our web-site

Thanks!
----- Original Message -----
From: "Brent Verner" <brent at rcfile.org>
To: <trilug at trilug.org>
Sent: Tuesday, November 06, 2001 6:12 AM
Subject: [TriLUG] data recovery - a modest how-to


> Hi,
>
>   I recently had an IBM-DTLA-307045 die on my box at work, and sure
> enough, I'd not backed up some (more than I'd care to lose) work
> in progress... panic.
>
>   The partition would not mount, nor fsck, due to read errors on the
> (primary) superblock, so I forcibly pulled everything off the partition
> that I could get, just incase I'd have to do a manual recovery ;-)
>
>   # dd conv=noerror if=/dev/hdc7 of=hdc7
>
> Let this guy run as long as it needs.  Next, try to see where a
> backup superblock is.  We can use this backup superblock instead of
> the primary superblock, since that one is /known/ to be inaccessible.
>
>   # mke2fs -n /dev/hdc7
>   mke2fs 1.25 (20-Sep-2001)
>   Filesystem label=
>   OS type: Linux
>   Block size=4096 (log=2)
>   Fragment size=4096 (log=2)
>   152960 inodes, 305605 blocks
>   15280 blocks (5.00%) reserved for the super user
>   First data block=0
>   10 block groups
>   32768 blocks per group, 32768 fragments per group
>   15296 inodes per group
>   Superblock backups stored on blocks:
>     32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208
>
> Ok, that last line is the location of backup superblocks, walk the
> list until we find a good one.
>
>   # e2fsck -b 32768 /dev/hdc7
>
> This rebuilt the filesystem so it could be mounted again and copy off
> the data.  Only one file (~/.bash_history) lost -- woohoo!!!
>
> Remember kids, backup.  But incase you don't, hopefully this might
> help someone out of the mess I found myself in :-)
>
> Oh yeah, if you happen to have one of the IBM-DTLA-307045 drives,
> replace it today.  A quick google search will reveal horrors of this
> model.  FWIW, I replaced the drive with one of IBM's IC35L040AVER07-0
> drives, which I surely hope isn't afflicted with whatever was causing
> the DTLA line to fail.
>
> cheers.
>   Brent
>
> --
> "Develop your talent, man, and leave the world something. Records are
> really gifts from people. To think that an artist would love you enough
> to share his music with anyone is a beautiful thing."  -- Duane Allman
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