SOLVED: Unable to mount ldm (dynamic disks partitions) in Linux

[FuriousGeorge]

I'm using dynamic disks so that I can use software raid on both windows and linux. It was working fine. Then I deleted and recreated some partitions (changes sizes, disk location, and order).

Now the work fine in windows, but I can no longer mount them using ntfs-3g.

$ sudo mdadm --build /dev/md5 -l 0 -n 2 -c 64 /dev/sda5 /dev/sdb5
mdadm: array /dev/md5 built and started.    

$ sudo ntfs-3g /dev/md5 /media/X/                                 
NTFS signature is missing.                                          
Failed to mount '/dev/md5': Invalid argument                                 
The device '/dev/md5' doesn't seem to have a valid NTFS.                           
Maybe the wrong device is used? Or the whole disk instead of a                        
partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?

The same thing happens with /dev/md3, which is also an NTFS partition.

Sadly, Linux user space tools still don't understand Windows LDM...

$ sudo fdisk -l /dev/sda

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x4b3b8b40

 Device Boot   Start    End   Blocks Id System
/dev/sda1       1   60802 488385528+ 42 SFS

... but the kernel does ...

 
$ cat /proc/partitions
major minor #blocks name

 8    0 488386584 sda
 8    1 104857600 sda1
 8    2  1572864 sda2
 8    3 41943040 sda3
 8    4  3145728 sda4
 8    5 336339968 sda5
 8    6  524288 sda6
 8   16 488386584 sdb
 8   17 104857600 sdb1
 8   18  1572864 sdb2
 8   19 41943040 sdb3
 8   20  3145728 sdb4
 8   21 336339968 sdb5
 8   22  524288 sdb6
 8   32 244198584 sdc
 8   36 41961780 sdc4
 9    1 209715072 md1
 9    2  3145600 md2
 9    4  3145664 md4
 9    6  524224 md6
 252    0  8388608 dm-0
 252    1  4194304 dm-1
 252    2  6291456 dm-2
 252    3  8388608 dm-3
 252    4  8388608 dm-4
 252    5  8388608 dm-5
 252    6 164626432 dm-6

So my hands may be tied to some extent with what I can do to fix it. I could use partimage, but I'm worried I would just be restoring a broken partition, and it could even end up more broken.

Maybe I will do this:

1. Boot Vista and Backup the two partitions in question
2. Boot linux, reformat the partitions with NTFS, at which point I would hopefully be able to mount them, and restore their data.

The only problem here is if I STILL can't mount them after formatting I will have a broken Windows.

Any ideas are much appreciated.

[FuriousGeorge]

Re: SOLVED: Unable to mount ldm (dynamic disks partitions) in Linux

First I tried my idea of backing up the partitions in windows followed by formatting and restoring from linux.

first i did an mdadm --create /dev/md3 -l 0 -n 2 -c 64 /dev/sda5 /dev/sdb5
then i did a mkfs.ntfs
then i mounted the partition as per normally and this time it worked.

then i boot windows, and it sees the partition as unformatted. cant do anything so I try from safemode.

in safe mode I can use disk management, so i delete the partition, recreate it, format it (not quick), and i still have the same problem.

Finally, I booted back into linux, used a combination of tar and partimage to backup kubuntu, and used fdisk to erase the partition tables.

then i booted to windows (windows C: is on a third disk which is not ldm) and recreated the partitions (can only be done from windows) the same exact way as before.

Luckily, not only can I now mount the Windows' LDM partitions from Linux, but since I remade the partitions exactly the same way as before I didn't even need to restore linux. All the data was intact.

That was simple.