fsck and mount disagree on whether superblocks are usable

[Julian H. Stacey]

Martin Cracauer wrote:
> Julian H. Stacey wrote on Mon, Feb 04, 2008 at 06:27:14PM +0100: 
> > Martin Cracauer wrote:
> > > Julian H. Stacey wrote on Sat, Feb 02, 2008 at 08:16:30PM +0100: 
> > > > Martin Cracauer wrote:
> > > > > This is not an emergency but I find it odd.  Mount and fsck agree on
> > > > > whether superblocks are usable.  Mount can mount readonly, but fsck
> > > > > can use neither the primary superblock nor the alternatives.
> > > > > 
> > > > > 32 is not a file system superblock
> > > > 
> > > > Just in case, You know secondary block on newer FSs moved from 32 ?
> > > > Ref man fsck_ufs
> > > >    -b      Use the block specified immediately after the flag as the super
> > > >              block for the file system.  An alternate super block is usually
> > > >              located at block 32 for UFS1, and block 160 for UFS2.
> > > 
> > > Thanks, Julian.
> > > 
> > > I'm honestly don't know how to tell whether I have ufs1 or ufs2.
> > 
> > I didnt either, but wanted to know & just found one way:
> > 
> > dumpfs /dev/____ | grep -i ufs
> 
> Yupp, there you go.

> The reason why it failed for me is that it was looking for the
> superblocks in the wrong place. 
> 
> This works:
> fsck_ffs -b 160 /dev/ad0s1a
> 
> I now need to debug why the target machine's fsck seemed to think it's
> ufs1 or why else it looked at 32 when the source machine didn't.

Yup, always nice to understand whats going on/went on, but at some
stage in your shoes, I'd copy all data to another place & then newfs
& copy back, for peace of mind :-)

-- 
Julian Stacey.  BSD Unix Linux Net Consultant, Munich.  http://berklix.com