topic Re: Bad superblock: Magic number wrong in Operating System - HP-UX

Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 04:52:59 GMT

fsck
BAD SUPER BLOCK: MAGIC NUMBER WRONG

How can I repair this error.
Some aplications doesn't work, CDE...
Please help.

Re: Bad superblock: Magic number wrong

Mark Grant — Fri, 05 Dec 2003 05:09:42 GMT

I assume this is a hfs filesystem.

try "fsck -F hfs -b 16 "

You need to use the raw device for the logical volume. I'm not entirely sure what you do if this is a vxfs filesystem as I cant see how a full fsck would work when the superblock is broken and I'm not sure if vxfs maintains alternative superblocks like HFS does.

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:16:02 GMT

Yes it is a HFS
fsck -F hfs -b 16 /dev/vg00/lvol3

Alternate suber block location: 16
fsck: /dev/vg00/lvol3: root file system
continue: y
BAD SUPER BLOCK: MAGIC NUMBER WRONG
USE -b ...

Now what....

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:21:07 GMT

Very interesant:
/etc/mnttab
/dev/vg00/lvol3 / vxfs log 0 1 1070617101

but in
/etc/fstab
/dev/vg00/lvol3 / hfs defaults 0 1

??????????????????????

Re: Bad superblock: Magic number wrong

Robert-Jan Goossens — Fri, 05 Dec 2003 05:24:53 GMT

Hi,

# mv /etc/mnttab /etc/mnttab.old
# mount -a
# more /etc/mnttab

Regards,
Robert-Jan

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:25:36 GMT

Had maybe edit this the -b 16 option???

In fact: The problem was that the user can't login in the cde, in prompt yes.
After login in black screen sandhour and again the cde login...
The user said, that he had reseted the computer (There is no reset!!!)

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:27:25 GMT

There is no mnttab.old, maybe I edit it.

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:28:48 GMT

shall i edit it

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:30:08 GMT

vxfs to hfs log to defaults.

Re: Bad superblock: Magic number wrong

Mark Grant — Fri, 05 Dec 2003 05:31:47 GMT

Firstly, use the raw device i.e /dev/vg00/rlvol1 not /dev/vg00/lvol1. The number after the -b option is to specify the location of alternate copies of the super block. You should be able to find a list of alternate super blocks in /var/adm/sbtab You should be able to use any of these values for the -b.

I would point out that I have nver managed to get one of the alternative super blocks to actually work but it's worth a try.

Re: Bad superblock: Magic number wrong

Robert-Jan Goossens — Fri, 05 Dec 2003 05:31:48 GMT

DO NOT EDIT THE MNTTAB,

recreate it

# mv mnttab mnttab.old
# mount -a

Robert-Jan

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:35:39 GMT

Ok I haven't mnttab.old
Maybe shall I:
cp /etc/mnttab /etc/mnttab.old
edit mnttab.old (vxfs to hfs log to defaults)
mv /etc/mnttab.old /etc/mnttab
??????????

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:43:25 GMT

Mark Grant
Your answer seens to work.
After ............ /rlvol1
No magic number at /rlvol1

but there is the same problem at /rlvol6
and /lvol3
But i only see at sbtab
/rlvol1: super-block backups

Re: Bad superblock: Magic number wrong

Elmar P. Kolkman — Fri, 05 Dec 2003 05:46:48 GMT

You say you wanted to change vxfs to hfs for the filesystem in mnttab... Are you really certain the filesystem is hfs, and not by any chance vxfs ???

Because in that case, perhaps fsck determined the wrong filesystem type, which could lead to this problem.

Re: Bad superblock: Magic number wrong

Fabio Ettore — Fri, 05 Dec 2003 05:51:31 GMT

Hi Bakos,

Robert and other forum people are right!

# mv /etc/mnttab /etc/mnttab.old
This command just renames the mnttab file.

# mount -a
This command re-mount filesystems in base of /etc/fstab.
After these actions you will see that /etc/mnttab and /etc/fstab should look the same.

I hope this helps you.

Best regards,
Ettore

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 05:52:03 GMT

I have some clone (I think only, I am since a week here) machines and on this machines is lvol3 hfs in mntab and fstab.
But in this problemfull machine is in fstab hfs and in mnttab vxfs

Re: Bad superblock: Magic number wrong

Robert-Jan Goossens — Fri, 05 Dec 2003 05:57:22 GMT

Oke,

# fsadm -F hfs /dev/vg00/rlvol3
file system : /dev/vg00/rlvol3
magic number : 95014
feature bits : 1
file system supports : nolargefiles, longfilenames

# fsadm -F vxfs /dev/vg00/rlvol3
fsadm: not a valid vxfs file system

My filesystem is hfs

# cd /etc
# mv mnttab mnttab.rjg
# mount -a

Yoy mnttab wil be recreated witk the mount command.

Robert-Jan

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 06:00:51 GMT

Ok I have this mv /etc/mnttab understand.
mount -a
...already mounted
at lvol6 that is the tmp : not a hfs file system, but in fstab yes.
On an another machine the mnttab and fstab are vxfs, also maybe the tmp is the problem for CDE.

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 06:06:29 GMT

# fsadm -F hfs /dev/vg00/rlvol3
is not a hfs file system

# fsadm -F vxfs /dev/vg00/rlvol3
nolargefiles, longfilenames

And now?...

Re: Bad superblock: Magic number wrong

Bakos György — Fri, 05 Dec 2003 06:26:59 GMT

Now I have edited in the fstab of lvol6 /tmp hfs to vxfs, it is now mounted.
But the CDE runs still not.(dr_dt no problem)
syslog.log nothing

By fsck lvol3 / BAD superblock
rlvol1 Last mounted on /stand
*******Marking file system clean****
*** File system was modified
vxfs fsck /lvol4-8 is currently mounted