How can I fsck a HD with bad super block

How can I fsck a HD with bad super block

Post by Weiping L » Thu, 26 Jun 1997 04:00:00



Hi, experts,

I have one 2GB Harddisk attached to my Solaris2.5.1 powered Sparc20
station. This HD has crashed once. I've partitioned it and formated
it.
But if I make "fsck -F ufs /dev/rdsk/c0t2d0sx", I got the message
"** c0t2d0s3
BAD SUPER BLOCK: MAGIC NUMBER WRONG
USE AN ALTERNATE SUPER-BLOCK TO SUPPLY NEEDED INFORMATION;
eg. fsck [-F ufs] -o b=# [special ...]
where # is the alternate super block. SEE fsck_ufs(1M).
"
I've changed the super block number with the option "-o b". It dones't
work also.

Have anyone a tip for this trouble.

Thanks

Weiping Li

 
 
 

How can I fsck a HD with bad super block

Post by Tom Ier » Thu, 26 Jun 1997 04:00:00


Quote:> Hi, experts,

> I have one 2GB Harddisk attached to my Solaris2.5.1 powered Sparc20
> station. This HD has crashed once. I've partitioned it and formated
> it.
> But if I make "fsck -F ufs /dev/rdsk/c0t2d0sx", I got the message
> "** c0t2d0s3
> BAD SUPER BLOCK: MAGIC NUMBER WRONG
> USE AN ALTERNATE SUPER-BLOCK TO SUPPLY NEEDED INFORMATION;
> eg. fsck [-F ufs] -o b=# [special ...]
> where # is the alternate super block. SEE fsck_ufs(1M).
> "
> I've changed the super block number with the option "-o b". It dones't
> work also.

> Have anyone a tip for this trouble.

> Thanks

> Weiping Li

Not an expert, (and please correct me if I'm wrong!), but:

newfs -N /dev/rdsk/c0t2d0s3

This will give you a list of superblocks. Pick one. Say it's 1024:

fsck -F ufs -o b=1024 /dev/rdsk/c0t2d0sx

This should use the alternate superblock 1024 to attempt to fsck.

Make sure you use the -N switch in the newfs or you will hose your filesystem!

Hope this helps.

--
Tom Ierna
Cox Target Media, Inc.
---
The views expressed in this electronic document are not necessarily
the views of my employer, Cox Target Media, Inc.

 
 
 

How can I fsck a HD with bad super block

Post by Pierre Merl » Fri, 27 Jun 1997 04:00:00


Hi

do a newfs -N and take another superblock.
Then use fsck -F ufs -o b=XXXXXX => your number.

Pierre

 
 
 

1. fsck won't run-Vol Mgr 2.6-Bad Super Blocks!

This is a long story...  I installed Volume Mgr 2.6 on Solaris 2.6 and
chose to encapsulate all disks (except boot/root) and upon rebooting it
couldn't encapsulate any of the 13 disks (except 1) and told me to run
fsck on them.  I can't run fsck (fsck -F ufs -o b=32 /dev/rdsk/c1t2d0s6)
it says magic number wrong BAD SUPER BLOCK!

Is there anyway I can restore the file system on these disks?  I do not
have a backup, this is my "test" system.  Can I run mkfs without
destroying all the data or am I totally screwed!!!???

Vol Mgr sees these disks now when I encapsulate them but there are no
volumes on them.  When I try to mount the volume I get an I/O error and
it doesn't know what the filesystem is when I do a
fstyp....Unknown_fstyp (no matches)!

I've talked to SUN Vol Mgr support for hours and hours we'd tried a lot
but I hope someone has some ideas for me... I'll try anything at this
point before I have to reinstall Oracle and all the other stuff that I
can't access right now.

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