Date: Thu, 4 Dec 2003 20:18:30 +0300 From: Sergey 'DoubleF' Zaharchenko <doublef@tele-kom.ru> To: scott@sremick.net Cc: FreeBSD <freebsd-questions@freebsd.org> Subject: Re: "Cannot find file system superblock" error - how to recover? Message-ID: <20031204201830.7c1c5de1.doublef@tele-kom.ru> In-Reply-To: <20031204162416.81350.qmail@web41103.mail.yahoo.com> References: <20031204180352.7c4e7571.doublef@tele-kom.ru> <20031204162416.81350.qmail@web41103.mail.yahoo.com>
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--Signature=_Thu__4_Dec_2003_20_18_30_+0300_tb1em55sQKUgl2kU Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: 7bit On Thu, 4 Dec 2003 08:24:16 -0800 (PST) "Scott I. Remick" <scott@sremick.net> probably wrote: > > --- Sergey 'DoubleF' Zaharchenko <doublef@tele-kom.ru> wrote: > > If you want to be more sure, try dd'ing your (suspectedly damaged) > > superblock and some of its (suspectedly OK) copies into different files: > > > > # dd if=/dev/ad6s1e skip=... bs=512 count=16 of=somefile > > > > As /usr/src/sys/ufs/ffs/fs.h suggests, for THE superblock skip should be > > 16 if you have UFS1 or 128 or 512 if you have UFS2 (if my maths is > > correct). These commands shouldn't do anything harmful to /dev/ad6s1e. > > Either I'm doing something wrong, or things aren't good. > > Given: > > su-2.05b# newfs -N /dev/ad6s1e Just a minute. Are you sure that the filesystem was newfs'd with the default parameters? If it were for me to newfs it, I would probably choose larger block&fragment sizes, as I would probably be storing large files. The superblock copy positions depend on the block/frag size. If you specify parameters different from those used for actually newfs'ing it the very first time, newfs -N will give you *incorrect* copy addresses! > /dev/ad6s1e: 76340.1MB (156344516 sectors) block size 16384, fragment size > 2048 > using 416 cylinder groups of 183.77MB, 11761 blks, 23552 inodes. > super-block backups (for fsck -b #) at: > 160, 376512, 752864, 1129216, 1505568, 1881920, 2258272, 2634624, 3010976, > > ... > > 152046368, 152422720, 152799072, 153175424, 153551776, 153928128, > 154304480, > 154680832, 155057184, 155433536, 155809888, 156186240 -- DoubleF The computing field is always in need of new cliches. -- Alan Perlis --Signature=_Thu__4_Dec_2003_20_18_30_+0300_tb1em55sQKUgl2kU Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) iD8DBQE/z2xwwo7hT/9lVdwRAuusAJ9VPmh5FQBsLTUxEE0w/2hju1aQUACfSiXg UsS7k2Kw/e+fzE1hW6jHZxw= =/doF -----END PGP SIGNATURE----- --Signature=_Thu__4_Dec_2003_20_18_30_+0300_tb1em55sQKUgl2kU--
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