data recovery

[Ken Moffat]

Javier Govea wrote:

>Hi,
>
>The hard disk of my Red Hat installation just crashed by some unknown reason. I'm trying
>to recover all data from the hard disk with no luck so far. 
>
>The linux recovery mode upon starting first told me that i don't have any partitions. But
>once i'm in the recovery mode i can list my partitions with fdisk -l. I can mount
>/dev/hda1 (my boot partition) using mount but it is mounted as ext2 (it should be ext3) I
>have access to almost all information in hda1 as an ext2 partition. 
>
>But the information i really want is in /dev/hda2. I cannot mount hda2, not even as ext2.
>If i try to mount hda2 as ext3 dmesg shows me this:
>
>hda: read_intr: status=0x59 { DriveReady SeekComplete DataRequest Error }
>hda: read_intr: error=0x40 { UncorrectableError }, LBAsect=261192, sector=4152
>end_request: I/O error, dev 03:02 (hda), sector 4152
>JBD: IO error reading journal superblock
>EXT3-fs: error loading journal.
>
>and fsck /dev/hda2 shows me:
>
>fsck 1.32 (09-Nov-2002)
>e2fsck 1.32 (09-Nov-2002)
>/: Attempt to read block from filesystem resulted in short read while reading block 519
>/: Attempt to read block from filesystem resulted in short read reading journal superblock
>fsck.ext3: Attempt to read block from filesystem resulted in short read while checking
>ext3 journal for /
>
>So, I think I have some damaged blocks. Is there any tool that I can use to recover my
>information? or to fix the damaged blocks? will e2fsck -c recover/fix something? i'm not
>very familiar with e2fsck, i don't want to run it until i'm completely sure i won't screw
>up my hard disk even more.
>
>Any help is very much appreciated.
>Thanx a lot
>X
>
>
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>

try turning off dma using hdparm.

or from recovery mode:
fsck -A -V ; echo == $? ==
see what it returns. If less than 4 you're ok.

If that doesn't work:
fsck -t ext2 -b 8193 /dev/hda
                        16385
                        24577

the spacing is 8192 assuming defaults. These are locations of backup 
superblocks.
(Linux Unleashed, 4th edition, pg. 580)


Hope this helps a bit.

-- 
Ken