[lug] Re: superblock erased by windows. Help! (II)

Deva Samartha blug-receive at mtbwr.net
Tue Feb 27 15:40:58 MST 2001

At 04:20 PM 2/27/01 -0500, you wrote:

>I tried e2fsck -b /dev/sda2 <8192*[1-20]+1 but without success.

you got the parameter sequence wrong if you did it the way above, device 
goes at the end, look at the man page!

e2fsck -b 8193 /dev/sda2

and if that does not work, increase the block number 16385 etc.

if you use -b /dev/sda7, it probably will try to convert the string  to 
integer/long, and of cause this is going to be wrong and of cause, there is 
no superblock there, if it's on the disk at all.

Also, if you use the -y option with fsck, sure, it's going through but it 
goes so fast that you don't see what is going on. I think to use the -y 
option in a damaged superblock situation, you are asking for trouble.

>Is there anyway to make a bakup of  my superblock to another
>computer, so ifthis happens again I can restore it?

There are plenty of spare superblocks on your filesystem which you can use 
when you use the e2fsck command with the correct parameters.

Copying a superblock to another medium and restoring it from there, I think 
you are asking for trouble.

Instead of backing up the superblock - you are backing up your important 
data regularly, I assume, so you are able to restore, in case the disk goes 
physically pooof?

Your question, why Windoze is hosing your Linux partition may be worth 
exploring - apparently, a program is crossing partition boundaries which is 
very strange - are you sure your disk geometry is correct? Is the BIOS's 
idea about the disk geometry the same as Linux's fdisk - well it's SCSI, so 
you may not see the geometry in the BIOS setup.

Maybe you'll need to clean something up in that area and then reinstall 
everything from scratch and restore data from backup?

If the wipeout of the superblock happens consistent - the partions may 
overlap and if one partition spills over to the next and writes there, at 
the beginning - what is there in Linux - superblock. And it gets hosed - 
just what you experience.

Again - can somebody post something about superblock restoring the "NT 
way". Something feels terribly wrong here. Isn't there dynamic information 
in the superblock - like end of free- and inodelist which would get wasted 
upon restore.


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