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Groups > comp.os.linux.setup > #2663

Re: No success repairing my ext4 file system so far, PLEASE HELP!

From Harry <simonsharry@gmail.com>
Newsgroups comp.os.linux.setup
Subject Re: No success repairing my ext4 file system so far, PLEASE HELP!
Date 2012-04-16 21:44 -0700
Organization http://groups.google.com
Message-ID <5903549.2603.1334637891638.JavaMail.geo-discussion-forums@pbcjp1> (permalink)
References (5 earlier) <PNFhr.60774$M%7.5669@newsfe10.iad> <87k41k20za.fsf@araminta.anjou.terraraq.org.uk> <jm9lhh$mjr$1@dont-email.me> <e5f364e8-ecb3-4651-86e9-f0ac9f97eb33@a8g2000pbe.googlegroups.com> <jmhqfi$rji$1@dont-email.me>

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On Tuesday, April 17, 2012 12:34:18 AM UTC+5:30, Doug Freyburger wrote:
> Harry wrote:
> > Doug Freyburger <dfrey...@yahoo.com> wrote:
> >
> >> According to the "fdisk -l" output there is a 250 MB parition in Linux
> >> format marked bootable.  Clearly /boot.  It does not fsck nor does it
> >> mount as /mnt/boot.  if only the boot code of the MBR were written that
> >> partition would fsck and mount.
> >
> > No, actually, I /can/ mount the boot partition sdb1.
> > ...
> > $ ls /mnt/x
> > config-3.2.5-3.fc16.i686.PAE
> > initramfs-3.2.9-1.fc16.i686.PAE.img
> > config-3.2.9-1.fc16.i686.PAE
> > initramfs-3.2.9-2.fc16.i686.PAE.img
> > config-3.2.9-2.fc16.i686.PAE                               initrd-
> > plymouth.img
> > config.mk-compat-wireless-3.3-rc1-2-3.2.5-3.fc16.i686.PAE  lost+found
> > config.mk-compat-wireless-3.3-rc1-2-3.2.9-1.fc16.i686.PAE
> > System.map-3.2.5-3.fc16.i686.PAE
> > config.mk-compat-wireless-3.3-rc1-2-3.2.9-2.fc16.i686.PAE
> > System.map-3.2.9-1.fc16.i686.PAE
> > efi
> > System.map-3.2.9-2.fc16.i686.PAE
> > grub
> > vmlinuz-3.2.5-3.fc16.i686.PAE
> > grub2
> > vmlinuz-3.2.9-1.fc16.i686.PAE
> > initramfs-3.2.5-3.fc16.i686.PAE.img
> > vmlinuz-3.2.9-2.fc16.i686.PAE
> 
> That's clearly a /boot mount point.  Conclusive evidence the partition
> table was not trashed.  No way did a "dd" copy all 250 MB.
> 
> >> According to the "vgimport -vvv" output posted here and the "pvscan"
> >> output posted on the forum there is a 79 GB partition in Linux LVM
> >> format that "should" contain the volume group vg_XYZ.  Neither vgimport
> >> nor vgscan works.
> 
> > I
> > have a cloned image of the bad sdb. Now what do I do with this image
> > using dd?  So far, I am able to fdisk bad.img as follows:
> >
> > $ losetup /dev/loop1 bad.img
> >
> > $ # If /dev/loop1 is not specified on the next line,
> > $ # then fdisk can't see it.
> > $ fdisk -l /dev/loop1
> >
> > Disk /dev/loop1: 80.0 GB, 80026361856 bytes
> > 255 heads, 63 sectors/track, 9729 cylinders, total 156301488 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/loop1p1   *        2048     1026047      512000   83  Linux
> 
> Definitely /boot
> 
> > /dev/loop1p2         1026048   156301311    77637632   8e  Linux LVM
> 
> And therefore this has to be what I would normally call VolGroup00 on he
> many Red Hat systems I have built.  In your posts you have called in
> vg_XYZ.

Well, the XYZ is placeholder for my, real 3-letter hostname. I thought, I would use XYZ instead of the actual hostname to keep the interaction as objective as possible. I don't mind revealing it if it would help in solve this problem, nothing secretive/personal about it.

For the same reason, though my shell prompt is also customized (via PS1) (it's actually a 2-line prompt!), I've been choosing to use only the plain, vanilla '$ ' in all my interactions so far.
 
> > vgscan reports no volumes.
> >
> > $ vgscan
> >   Reading all physical volumes.  This may take a while...
> >   No volume groups found
> >
> > Now, what to do next?
> 
> That's the puzzle we have gotten to.  It's nowhere near where you did
> the dd.  Is there any chance the dd actually had the partition in its of
> clause?  "of=/dev/sdb2".  If so that trashed the configuration blocks of
> the volume group not the MBR and partition table.  So I move on to the
> next speculation.  If you are positive it was "of=/dev/sdb" with no
> number none of the rest applies.

I am absolutely positive that I issued the 

    $ dd if=/dev/sdb of=/dev/sda bs=446 count=1

command. (Recap Note: What is sdb now, was sda earlier... at the time the dd command was issued.)

I was well aware of the dangers of playing with 'dd', and so was extra, extra careful in constructing it before issuing it. Though I didn't (and still don't deeply) understand partitioning and LVM, esp the way all you folks do, when issuing the dd command I knew at least things like device vs partition, if= vs of=, bs, count, skip, 446-byte MBR code, etc. As I said earlier, I was so confident of what I was doing that I didn't think it necessary to backup the disk!

Even during Fedora 16 install, when I came to this step 
    http://docs.fedoraproject.org/en-US/Fedora/16/html/Installation_Guide/Assign_Storage_Devices-x86.html
, I remember VERY clearly:
    1. leaving this (currently messed up 80G) disk in the Data Storage Devices listbox; and 
    2. including the new 250 G disk in the Install Target Devices listbox.

Then, a few steps later, at http://docs.fedoraproject.org/en-US/Fedora/16/html/Installation_Guide/s1-diskpartitioning-x86.html, I remember VERY clearly /not/ having the 80G disk selected for formatting. 

Could any of this have possibly messed up my disk? Probably not. 

Later, I did incorrectly and unsuccessfully try various e2* commands to repair the LVM partition mistaking it for an ext4 fs. Only this part I don't remember fully well; I think, I did use the '-n' option in these commands which would have left the disk intact. Also, because I was simply copy-pasting commands from the Net without really understanding them (relying on the assurance of '-n') and because I tried various permutations of device/partition and offset numbers, I didn't really note down what all I was doing. Thus, except for these various e2* command sequences that I don't fully recall now, I'm absolutely sure of everything else.

> That is consistent with the results - It won't boot because there's no /
> because there's no vg_XYZ because the volume group table had the first
> 442 bytes overwritten.
> 
> Volume groups do have configuration data and it can be recovered. 
> Maybe.  When you started the thread you wer elooking for alternate
> superblocks.  Volume groups do have tables that work sort of like that. 
> I had hoped that "vgscan" would look for alternate copies.
> 
> I take it there was not a second drive in vg_XYZ?  Alternate copies go
> on every drive.  Not sure what other tools to use if there was a single
> disk.  I build commercial systems with mirrored boot for reasons like
> this.  Or at least bootable kickstart images on DVD-ROM.  So at this
> point I've run to the end of my rope.
> 
> Tools like PartitionMagic look into partitions.  You need a tool like
> VolumeGroupMagic.  If there is such a tool.  If there is I want one to
> add to my war chest marked "Just because you're paranoid doesn't mean
> they are out to get you".

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Thread

No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 03:29 -0700
  Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 11:46 +0100
    Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 04:08 -0700
      Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 12:36 +0100
        Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 05:25 -0700
          Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 13:49 +0100
            Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 06:09 -0700
              Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 19:18 +0100
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 11:49 -0700
              Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-12 18:27 +0000
              Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-12 18:51 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 12:12 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2012-04-12 17:15 -0400
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 20:30 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 06:58 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 07:13 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-13 19:29 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 21:27 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-14 07:58 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-14 06:35 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-14 19:59 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-14 19:58 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-14 20:13 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-15 15:14 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 02:39 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-16 08:50 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 08:02 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 10:39 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 11:08 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-16 15:58 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 23:02 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Robert Nichols <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-17 10:58 -0500
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-18 21:53 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-19 16:45 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-19 18:34 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-20 17:19 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-21 20:37 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-25 16:01 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-28 16:32 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-16 19:15 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 21:20 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 21:40 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 21:56 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-16 18:47 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 20:19 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-13 15:22 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! J G Miller <miller@yoyo.ORG> - 2012-04-13 17:13 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 21:58 -0700
          Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 15:50 +0000
            Re: No success repairing my ext4 file system so far, PLEASE HELP! The Natural Philosopher <tnp@invalid.invalid> - 2012-04-12 21:37 +0100
      Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 15:46 +0000
        Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 09:35 -0700
          Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 18:57 +0000
  Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-12 15:59 +0000
    Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 16:39 +0000
      Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 09:53 -0700
        Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 19:03 +0000
    Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 09:48 -0700
      Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 19:07 +0000
    Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 18:43 +0100
      Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 10:55 -0700
      Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-12 18:07 +0000
        Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 19:20 +0100
          Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 19:11 +0000
            Re: No success repairing my ext4 file system so far, PLEASE HELP! Richard Kettlewell <rjk@greenend.org.uk> - 2012-04-12 20:39 +0100
              Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-13 16:50 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-13 21:24 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Doug Freyburger <dfreybur@yahoo.com> - 2012-04-16 19:04 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-16 21:44 -0700
                Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-17 17:18 +0000
                Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-17 18:41 -0700
      Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 19:09 +0000
    Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 10:46 -0700
      Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 19:13 +0000
        Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-12 12:21 -0700
          Re: No success repairing my ext4 file system so far, PLEASE HELP! unruh <unruh@invalid.ca> - 2012-04-12 20:12 +0000
  Re: No success repairing my ext4 file system so far, PLEASE HELP! g.fink@gmx.net (Gernot Fink) - 2012-04-12 18:20 +0000
  Re: No success repairing my ext4 file system so far, PLEASE HELP! The Natural Philosopher <tnp@invalid.invalid> - 2012-04-12 21:35 +0100
  Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-19 06:43 -0700
    Re: No success repairing my ext4 file system so far, PLEASE HELP! Bob <SEE_SIGNATURE@localhost.localdomain.invalid> - 2012-04-19 11:29 -0500
      Re: No success repairing my ext4 file system so far, PLEASE HELP! Harry <simonsharry@gmail.com> - 2012-04-19 18:50 -0700

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