unable to read superblock

[Barry Gamblin]

Have a disk on a 595 that isn't coming up. When I try to fsck the
drive, it says:
Unable to read superblock (TERMINATED).

Is there an alternate superblock (like block 32 in Solaris) and what is
the fsck syntax to use it? If not, what other alternatives do I have to
try and recover the drive?

Thanks.

--
__________________/\__ Barry S. Gamblin, barry_...@nrel.gov
(_________________/__\_) National Renewable Energy Laboratory
/ \ 1617 Cole Blvd., Golden CO 80401
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[Scott L. Fields]

There are other questions to ask. If you can't read the superblock,
it indicates a problem on the base media and not the filesystem.

What disks are the source filesystem on? Are they all active (lsvg -p
<vgname>)?
Does the error report show disk errors for any of these disks? If so, the
real
issue is to resolve the overall disk problems.

Barry Gamblin wrote in message <36D1C5C4...@nrel.gov>...

[dave]

Barry Gamblin wrote:

> Have a disk on a 595 that isn't coming up. When I try to fsck the
> drive, it says:
> Unable to read superblock (TERMINATED).
>
> Is there an alternate superblock (like block 32 in Solaris) and what is
> the fsck syntax to use it? If not, what other alternatives do I have to
> try and recover the drive?
>

> Thanks.
>

When you say a disk "isn't coming up", exactly what do you mean? I think
I can guess ...
If you see the message "Unable to read superblock", that is most often
exactly what it means, it is unable to read the superblock off the media.
There is a backup superblock, but it's contained on the same disk as the
primary (unless your using mirroring, which I don't think is the case
here). So, if you can't read the primary superblock because the disk has
failed or is failing, you won't be able to read the backup either. You
didn't mention what version of AIX your running, but if it is post 4.x, the
command 'fsck -p /dev/lvname," or If it is version 3.x, then "dd count=1
bs=4k skip=31 seek=1 if=/dev/lvname of=/dev/lvname" will copy the backup
superblock over the primary. I seriously doubt these will help you though,
it sounds as if the drive has failed. If that is the case, then you need
to contact a company that specializes in recovering data from failed disk
drives, unless of course you have a current backup. If you have a current
backup, then you would simply recreate the filesystem and restore from the
backup. Be warned, companies that do hardware data recovery don't do it
for free......they usually charge quite a bit for the service. But, since
we are talking Government here, and specifically my tax dollars, I KNOW you
have a current backup, eh?