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Date: Sat, 24 Jul 2004 05:55:10 -0700
From: Tim Kientzle <kientzle@freebsd.org>
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To: Charles Sprickman <spork@fasttrackmonkey.com>
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cc: freebsd-hackers@freebsd.org
Subject: Re: disk recovery help
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Charles Sprickman wrote:
> 
> ...  there seem to be a ton of superblock backups.
> How do I find out where they are and compare them?

This is an FAQ, and probably in the handbook somewhere
(google for "alternate superblock"):

   * According to "man fsck_ffs", block 32 is usually
     an alternate superblock.

   * You can also use newfs -N to find out where
     the superblocks are probably located and
     fsck_ffs -b to recheck the drive using
     one of the alternates instead of the trashed
     primary.

   * 40G IDE drives are cheap and plenty big enough
     to give you a sandbox for trying to recover
     your 26G filesystem image.

Someone else mentioned "fsdb."  I've never used
it myself, but it looks like it might be useful to you.

Tim