Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!tut.cis.ohio-state.edu!rutgers!ucsd!brian
From: brian@ucsd.Edu (Brian Kantor)
Newsgroups: comp.unix.wizards
Subject: Re: fsck fails...help!
Keywords: fsck
Message-ID: <10011@ucsd.Edu>
Date: 17 Sep 89 21:05:27 GMT
References: <9171@pyr.gatech.EDU> <726@anasaz.UUCP> <730@anasaz.UUCP>
Reply-To: brian@ucsd.edu (Brian Kantor)
Organization: The Avant-Garde of the Now, Ltd.
Lines: 16

A 4.3BSD filesystem will have alternate superblocks; you may be able to
use one of them to get your filesystem back into shape enough to dump it
off to tape.  fsck -b is the option.  On most of the system I work with
(Vaxen, Suns, etc) the first alternate superblock is at 32; I have seen
it elsewhere (on a Pyramid).

Really heroic measures to recover something you should have been backing
up include using 'dd' to copy the damaged filesystem off to one of your swap
partitions (use conv=noerror), then fsck'ing THAT and copying it back,
or dd'ing it off to tape and back in to rewrite the bad blocks and then
fsck'ing it, etc.  The concept is to get it to the point where you can
get the data off to somewhere else and re-mkfs the file system, perhaps
after reformatting the bad spots on the disk.

Then go have a beer and plan a more robust backup scheme.
	- Brian