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From: Florian Erfurth on 2 Mar 2010 16:40
Hi,
filesystem autodetect doesn't work well on a partition (/dev/sdc) so I
cannot just mount without fs-type as parameter. I found out that sdc1 is
missing in blkid output. Outputs says more than words:

floh(a)athlon:~$ sudo fdisk -l /dev/sdc

Disk /dev/sdc: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x99909990

Device Boot Start End Blocks Id System
/dev/sdc1 * 1 9729 78148161 7 HPFS/NTFS


You see, there is a NTFS-partition on sdc.


floh(a)athlon:~$ sudo blkid -p /dev/sdc1
/dev/sdc1: ambivalent result (probably more filesystems on the device)


Why??? How can I print all(?) filesystems of sdc1?
In same machine on other harddisk there is another ntfs-partition which is
ok (and mount with fs-autodetect works fine and is listed in blkid):

floh(a)athlon:~$ sudo blkid -p /dev/sdd1
/dev/sdd1: UUID="cd040edc-e386-4b30-88e2-8e44f87b96b1" VERSION="1.0"
TYPE="ext3" USAGE="filesystem"

Idea? I'm not sure but I believe there are still superblocks of softwareraid
on this partition. This harddisk was used for softwareraid before. I tried
to fill superblock with zeros. I had likely the same problem in last year.
Not sure what exactly was wrong but following command resolved the problem
on other harddisk, which was used for softwareraid too. But this time it
didn't help:

floh(a)athlon:~$ sudo mdadm --zero-superblock /dev/sdc
mdadm: Unrecognised md component device - /dev/sdc

Thank you!
Floh
From: David W. Hodgins on 3 Mar 2010 03:07
On Tue, 02 Mar 2010 16:40:25 -0500, Florian Erfurth <floh-erfurth(a)arcor.de> wrote:

> floh(a)athlon:~$ sudo fdisk -l /dev/sdc
> /dev/sdc1 * 1 9729 78148161 7 HPFS/NTFS
> You see, there is a NTFS-partition on sdc.

I see that there is a partition listed in the partition table
of the mbr, that has type set to x'07', aka ntfs.

> floh(a)athlon:~$ sudo blkid -p /dev/sdc1
> /dev/sdc1: ambivalent result (probably more filesystems on the device)

Have you formatted the filesystem on that partition?

Try running (as root) "mkfs.ntfs -L somelabel /dev/sdc1".

Regards, Dave Hodgins

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From: Florian Erfurth on 3 Mar 2010 03:36
David W. Hodgins wrote:

> On Tue, 02 Mar 2010 16:40:25 -0500, Florian Erfurth
> <floh-erfurth(a)arcor.de> wrote:
>
>> floh(a)athlon:~$ sudo blkid -p /dev/sdc1
>> /dev/sdc1: ambivalent result (probably more filesystems on the device)
>
> Have you formatted the filesystem on that partition?

Yes, its formatted by WinXP and already used in WinXP (for user datas). So I
don't need to "kill" the datas with mkfs.ntfs. ;)

Thank you!
Floh
From: David W. Hodgins on 3 Mar 2010 16:10
On Wed, 03 Mar 2010 03:36:16 -0500, Florian Erfurth <floh-erfurth(a)arcor.de> wrote:

> Yes, its formatted by WinXP and already used in WinXP (for user datas). So I
> don't need to "kill" the datas with mkfs.ntfs. ;)

Assuming it's the software raid superblock that's being found,
http://www.linuxfoundation.org/collaborate/workgroups/linux-raid/superblock
explains the location for the various linux software raid versions.
I've skimmed through the blkid source code, and for software raid,
it's looking for 0xa92b4efc, which matches what's shown for in the
format page linked to, from the above page.

The "mdadm --zero-superblock" may need the --force option, to
force overwriting, but I'd make sure a full backup was available,
just in case.

If the version of software raid previously used was "ancient",
and the currently used version of mdadm is not, it may not
be finding the superblock, which will be at the end of the
device. You may be able to overwrite it, just by writing to
a file, to fill the filesystem.

Regards, Dave Hodgins

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From: Florian Erfurth on 9 Mar 2010 18:21
David W. Hodgins wrote:

> On Wed, 03 Mar 2010 03:36:16 -0500, Florian Erfurth
> <floh-erfurth(a)arcor.de> wrote:

Hi, sorry about taking long time, but I had to get some space for backup
data of ntfs-partition.

> explains the location for the various linux software raid versions.
> I've skimmed through the blkid source code, and for software raid,
> it's looking for 0xa92b4efc, which matches what's shown for in the
> format page linked to, from the above page.
>
> The "mdadm --zero-superblock" may need the --force option, to
> force overwriting, but I'd make sure a full backup was available,
> just in case.

It didn't help because I got error-text like:
mdadm: option --zero-superblock not valid in manage mode

Instead of this I formatted the partition in WinXP, and now the Problem is
gone. I forgot to try your suggestion to fill the remaining space of the
partition with zeros. But thank you! :)
I believe the problem was caused by superblock of softwareraid and the ntfs-
partition was probably formatted in quick-mode (this time I did real
format).

cu Floh
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