Date: Tue, 12 Jan 1999 00:56:05 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: eivind@FreeBSD.ORG (Eivind Eklund) Cc: tlambert@primenet.com, fs@FreeBSD.ORG Subject: Re: Finding a lost FS Message-ID: <199901120056.RAA22622@usr08.primenet.com> In-Reply-To: <19990111232558.W40114@bitbox.follo.net> from "Eivind Eklund" at Jan 11, 99 11:25:58 pm
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> > > An error during some build experiments made disklabel run against the > > > wrong disk, overwriting just the label before quitting. Have anybody > > > got any good starters for how to recover the information on where the > > > FS on that disk is located? > > > > > > I'm presently just running fsck -n -b <all numbers> against the disk, > > > looking for alternate superblocks with good checksums. This has also > > > uncovered at least one bug in fsck (it gives a bus error when scanning > > > the bogus 'file system' described by one of those superblocks), so it > > > is probably an exercise I should do more regularly... > > > > Did you blow the label on the other disk, or just the superblock for > > the FS in question? > > Label :-( > > > If you blew the label, you have to recreate it correctly, since fsck > > is for checking FS's, not disklabel's that define where FS's start. > > I did that just to find the alternate superblocks, hoping to be able > to use their location to give me a clue to the correct labelling of > the disk. That has not quite worked yet :-( Ah. You need to search for the FFS "magic number", which will be in the first superblock of each FS partition. You only need to look at cylinder boundaries (if you were careful), and it's a pretty quick scan. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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