Re: "Cannot find file system superblock" error - how to recover?

From: Scott I. Remick (scott_at_sremick.net)
Date: 01/06/04

  • Next message: Derek Marcotte: "Poor SCSI disk preformance" 
    Date: Tue, 6 Jan 2004 06:31:08 -0800 (PST)
To: Sergey 'DoubleF' Zaharchenko <doublef@tele-kom.ru>

    --- Sergey 'DoubleF' Zaharchenko <doublef@tele-kom.ru> wrote:
    > And maybe prefix that by a
    >
    > $ bsdlabel -R /dev/ad6s1c dislabel.ad6s1c.new
    >
    > which would just check your new layout for errors, without writing
    > anything, and print your file out as disklabel understands it.

    So you're saying, run it as user and not root for the sake of testing it in
    a read-only setting? Would that be better than using -n? From the man page:

    "The -n stops the bsdlabel program right before the disk would have been
    modified, and displays the result instead of writing it."

    > > > And lastly... your talk about offsets. The man page for bsdlabel
    > describes
    > > > using it on the whole disk (ad6) and not a slice or partition. If I
    > run it
    >
    > It can't be fdisk that you are reading about?

    Nope. "man bsdlabel" mentions:

    "disk represents the disk in question, and may be in the form da0 or
     /dev/da0. It will display the partition layout."

    But I see now all the later examples mention da0s1 so maybe I misunderstood.

    > And the `new' one seems to be correct for a 80G drive (+- a couple of
    > megabytes)? Have you touched anything?
    >
    > Now, mount might work.

    Haven't changed anything yet. Which one are you calling the "new" one? Mount
    would be done on the partion (ad6s1c) which gives errors with bsdlabel and
    has an offset of 63, not the whole slice (ad6s1) which has an offset of 0
    and doesn't give errors (with bsdlabel).

    > Uhum. disklabel said that the offset was 63 in your previous posting,
    > didn't it?

    63 for ad6s1c, 0 for ad6s1. This is what's got Malcolm confused.

    > What does
    >
    > # ls -l /dev/ad6s1 /dev/ad6s1c
    >
    > say? Any differences? I have none.

    su-2.05b# ls -l /dev/ad6s1 /dev/ad6s1c
    crw-r----- 1 root operator 4, 20 Dec 29 08:11 /dev/ad6s1
    crw-r----- 1 root operator 4, 21 Dec 29 08:11 /dev/ad6s1c

    And to recap:

    su-2.05b# bsdlabel /dev/ad6s1
    # /dev/ad6s1:
    8 partitions:
    # size offset fstype [fsize bsize bps/cpg]
      c: 156344517 0 unused 0 0 # "raw" part, don't
    edit
      e: 156344517 0 4.2BSD 2048 16384 89

    su-2.05b# bsdlabel /dev/ad6s1c
    # /dev/ad6s1c:
    8 partitions:
    # size offset fstype [fsize bsize bps/cpg]
      c: 156344517 63 unused 0 0 # "raw" part, don't
    edit
      e: 156344517 63 4.2BSD 2048 16384 89
    partition c: partition extends past end of unit
    bsdlabel: partition c doesn't start at 0!
    bsdlabel: An incorrect partition c may cause problems for standard system
    utilities
    partition e: partition extends past end of unit

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  • Next message: Derek Marcotte: "Poor SCSI disk preformance"

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