wrong partion header

If you have a question about a file system (for example xfs, reiserfs, ...)

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dangerseeker
Posts: 2
Joined: Thu Dec 14, 2006 1:57 pm

wrong partion header

Postby dangerseeker » Thu Dec 14, 2006 2:32 pm

Hi,

I'm new and I have a problem. ;-)

I want to use partimage on a (working) NTFS partition that is *wrongly* detectet by partimage as "reiserfs".

How do I change the partition header to show the correct filesystem type so partimage can back up my partition?

Kind regards

dangerseeker

fdupoux
Site Admin
Posts: 26
Joined: Sat Feb 21, 2004 12:12 pm

Postby fdupoux » Sat Dec 16, 2006 11:53 am

The reiserfs header is located around offset 64KB in the partition. Maybe your ntfs was a reiserfs disk before. You may erase it by hand but that's dangerous, be carreful

Have a look at the "magic string" "ReIsEr2Fs"
http://homes.cerias.purdue.edu/~florian ... iserfs.php

dangerseeker
Posts: 2
Joined: Thu Dec 14, 2006 1:57 pm

wrong partion header: Solved

Postby dangerseeker » Sat Dec 16, 2006 1:41 pm

Thank you for your answer.
I did this later the day I posted here and it worked. Luckily! It felt like a brain surgery with hammer and chisel. 8-(

And your guess was absolutely right, the partition was formated as ReiserFS before, but I was unaware of NTFS not claming the whole partition and leaving the ReiserFS "magic bytes" behind, which can be quite annoying.

I must confess the concept of "partition header" was totaly new to me, even having played with bootblocks and masterbootrecord a bit and using Linux on a daily basis.

Is there any documentation in filesystems to close that "knowledge gap" or is this topic too arcane (or too specific) for the mortal mind to understand?


Thankfully Yours

dangerseeker

mnemonic76
Posts: 1
Joined: Thu Dec 21, 2006 11:37 pm

OS/2 Boot manager partition registers as fat32

Postby mnemonic76 » Thu Dec 21, 2006 11:45 pm

I have a similar problem (I think).

I am trying to use partimage 0.6.4 under Knoppix 4 to create an image file of an OS/2 Boot Manager partition.

Cfdisk and Sfdisk both see the partition with the correct filesystem type, but partimage sees it as fat32.

When I try to create the image I get an error "Can't read FSinfo sector" which I think is a sector in a fat32 filesystem.

I tried changing the filesystem type (code) with sfdisk to a different type, but it seems that partimage is ignoring that.

Can anyone tell me how partimage determines filesystem type?

thanks in advance... I'm going nuts with this one!

mnemonic76

fdupoux
Site Admin
Posts: 26
Joined: Sat Feb 21, 2004 12:12 pm

Postby fdupoux » Thu Dec 21, 2006 11:48 pm

Partimage ignore all filesystem codes you could set with fdisk. It only determines the FS with the contents of the partition. Is your partition a reiserfs ?

reiserfs has 64 KB unused at the beginning, and it may contains a FAT32 bootsector. Try to erase it (dangerous !!!):
dd if=/dev/zero of=/dev/xxx count=1 bs=512

You should backup your bootsector before:
dd if=/dev/xxx of=backup count=1 bs=512


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