where to RTFM about disk errors

[Mark Street]

Good!!!  My improper assumption that you had 1k block size....  At least it 
got your juices flowing...

 From the e2fsck manpage...

-b superblock
               Instead of using  the  normal  superblock,  use  an
               alternative  superblock  specified  by  superblock.
               This option  is  normally  used  when  the  primary
               superblock has been corrupted.  The location of the
               backup superblock is dependent on the  filesystem's
               blocksize.   For  filesystems with 1k blocksizes, a
               backup superblock can be found at block  8193;  for
               filesystems with 2k blocksizes, at block 16384; and
               for 4k blocksizes, at block 32768.

               Additional backup superblocks can be determined  by
               using  the  mke2fs  program  using the -n option to
               print out where the superblocks were created.   The
               -b  option  to mke2fs, which specifies blocksize of
               the filesystem must be specified in order  for  the
               superblock  locations  that  are  printed out to be
               accurate.


At 11:19 AM 7/19/2002 -0700, Bob Blick wrote:

> > On ext2 filesystems backup superblocks occur every 8192 bytes so you should
> > have one at 8193 and 16385 ..... etc.
> >
> > e2fsck -b 16385 /dev/hd**
>
>Thanks Mark!
>
>It turns out since it's a big drive, the first extra superblock is at
>32768, so now e2fsck is happily chugging along and is finding many blocks
>shared among 7 files. I guess I'll start answering Y and see what is left
>of those files after I'm done.
>
>BTW I found the superblock locations by running mke2fs like this:
>mke2fs -n /dev/hda4
>
>Also funny to note that on a small drive the first backup would be at
>8193, but the second is at 16384, not 16385 as one would normally infer
>from the unlikely number 8193. I'm not curious enough to find out why :)