Date: Mon, 5 May 2003 14:04:35 -0700 (PDT) From: Paul English <penglish@hydro.washington.edu> To: "Greg 'groggy' Lehey" <grog@FreeBSD.org> Cc: freebsd-questions@FreeBSD.org Subject: Re: Incorrect super block on a disk Message-ID: <20030503183948.W10431-100000@dynamic.hydro.washington.edu> In-Reply-To: <20030504005204.GK84427@wantadilla.lemis.com>
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On Sun, 4 May 2003, Greg 'groggy' Lehey wrote: > > it tries for an alternate superblock, fails and then I try doing > > fsck -b 32 (as recommended in the manpages) and I get the same error. > > > > Is there anything I'm doing wrong or something else to try? > > It seems pretty certain that whatever they sent back from the data > recovery house is not a UFS file system. You should try to find out > how they got the data there. I can't imagine them creating a new file > system. Until you know that, there's not much point trying > alternatives, though some of them exist. I will check with them - it looks like they don't have someone I can talk to on Saturday. I believe though that they just did a bit-for-bit or byte-for-byte copy. The partition table information is still there - the output of disklabel shows what appears to me to be a valid disk label for all of the partitions, this one included. > > Can I somehow regenerate the super block? > > Regenerating super blocks is simple: that's what newfs(8) does. The > trick is keeping your data. Aah... Fortunately they still have the source data, and I can also do a dd of the partition to another drive before I go mucking with newfs. I don't suppose that newfs has a special option to just try to regenerate superblocks and save the data? In my web searching for solutions, it looks like Linux has a -S option for mke2fs that will attempt to rebuild superblocks while saving the data. Are there any other alternate superblocks? Again it appears that Linux saves them every 8K clusters, but the fsck manpage on freebsd only mentions that block 32 is usually an alternate. Paul
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