XFS-Partition trashed? - Setup

This is a discussion on XFS-Partition trashed? - Setup ; Hello, i'm not sure if this is the right group to post filesystem problems to, but i couldn't find one for filesystems, so i try asking here. Please correct me if there's a petter place to ask on this topic. ...

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Thread: XFS-Partition trashed?

  1. XFS-Partition trashed?

    Hello,

    i'm not sure if this is the right group to post filesystem problems to,
    but i couldn't find one for filesystems, so i try asking here.
    Please correct me if there's a petter place to ask on this topic.

    Yesterday, i just wanted to reenable the boot ability of my XP-Partition
    and later rewrite lilo to be able to boot both OSs again.

    The layout is as follows:
    hda1(swap)
    hda2(extd)
    hda5(ntfs)
    hda3(ext3)
    hda4(xfs)

    I booted into the recovery console of the XP-CD and did a "fixboot", but
    forgot to set the NTFS-partition (hda5) as active first, so fixboot
    trashed my XFS-partition with FAT12 and a new bootsector in it.


    Though i already googled and read manpages (testdisk,xfsprogs,etc.), i'm
    not sure if i can restore my beloved debian installation with lots of
    data.
    And no, i've got no recent backup...

    Before i try to write anything to the harddisk/partition table/partition
    types, i'd like to make sure that i do the right steps.

    So i'm asking if it is possible to restore the XFS-filesystem, maybe
    simply by setting the partition type to 83 and doing something
    xfs-related magic.

    I really hope that someone here knows about XFS and if/how it is
    possible.
    --
    lg & regards, Niko
    ________________________________
    Verfallen wir nicht in den Fehler, bei jedem Andersmeinenden entweder an
    seinem Verstand oder an seinem guten Willen zu zweifeln. (Otto von
    Bismarck)


  2. Re: XFS-Partition trashed?

    On Fri, 10 Aug 2007 18:50:42 +0200, Nikolai Försterling wrote:

    > Hello,
    >
    > i'm not sure if this is the right group to post filesystem problems to,
    > but i couldn't find one for filesystems, so i try asking here.
    > Please correct me if there's a petter place to ask on this topic.
    >
    > Yesterday, i just wanted to reenable the boot ability of my XP-Partition
    > and later rewrite lilo to be able to boot both OSs again.
    >
    > The layout is as follows:
    > hda1(swap)
    > hda2(extd)
    > hda5(ntfs)
    > hda3(ext3)
    > hda4(xfs)
    >
    > I booted into the recovery console of the XP-CD and did a "fixboot", but
    > forgot to set the NTFS-partition (hda5) as active first, so fixboot
    > trashed my XFS-partition with FAT12 and a new bootsector in it.
    >
    >
    > Though i already googled and read manpages (testdisk,xfsprogs,etc.), i'm
    > not sure if i can restore my beloved debian installation with lots of
    > data.
    > And no, i've got no recent backup...
    >
    > Before i try to write anything to the harddisk/partition table/partition
    > types, i'd like to make sure that i do the right steps.
    >
    > So i'm asking if it is possible to restore the XFS-filesystem, maybe
    > simply by setting the partition type to 83 and doing something
    > xfs-related magic.
    >
    > I really hope that someone here knows about XFS and if/how it is
    > possible.
    >

    I don't know how bad you have broken your filesystem. I am guessing that
    it could be very bad, and the problem is magnified by not having a backup.
    If your data is worth saving, stop using your system and get professional
    help with this problem.

    It has been quite a while since I studied the FAT filesystem. I reviewed
    some documentation that I have about FAT, and the operations that the
    format command may have executed. The size of the FATs which are
    written after the BPB depends on the size of the disk. I assume FAT can
    use 12-bit, 16-bit, or 32-bit based cluster offsets. My documentation only
    covered 12-bit and 16-bit based cluster counts. The format likely damaged
    an area of the disk by zeroing it to use as the FATs. My documentation
    stated that format usually creates a primary FAT, and a secondary FAT; the
    number of redundant FATs is a variable.

    I haven't studied the internal workings of XFS. I use it, though. I know
    that it is a journalled filesystem using balanced-trees. I don't know
    where it stores key indexes, or how rendundant the indexes are. I would
    guess that if certain key structures which describe the disk layout were
    damaged by overwriting, then recovery could be very difficult. This is
    where professional assistance may be helpful. However, finding the right
    professional service may be a difficult problem, too. I would guess most
    recovery services are setup to help with recovering Windows-based
    filesystems. But without the working indexes, finding your data could be
    similiar to finding a needle in a haystack. However, if you only lost the
    text to your novel, then you might be able to recover some or all of it
    easily. It just depends on a lot of things, including your expectations.

    --
    Douglas Mayne

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