I'm running Ubuntu 8 something and my data is on a mirrored pair of 1TB disks formatted as ext3, and the RAID is via mdadm. I want to move to Windows 7 (yeah yeah I know but Linux aint doing it for me at the moment) and migrate the disks to NTFS. My plan is:

Break the MDADM RAID (by failing one disk logically) Format the 'failed' disk as NTFS Copy data from the RAID array to the NTFS disk (dont care about perms)

Install Windows, (new separate non RAid disk) and my data disk is available.

I've researched this and it seems the easiest way. I dont have another disk to back up to so I think this is my only way. Can anyone see a better/easier way?

  • 4
    You might want to trigger an array check before you proceed. – Zoredache Nov 30 '09 at 9:48
  • You've probably already thought of this, but it will only work if you're using RAID 1. – Kevin M Feb 3 '10 at 14:47


mdadm --fail /dev/sda<n>  (The software raid partition of drive)
more /proc/mdstat   (To verify that the partition is indeed marked failed)
mdadm --remove /dev/sda<n>  (The same partition which was marked fail)
fdisk  /dev/sda   (Then change partition type to fat32 using 't' option) 

I am not sure whether you can format partition as NTFS using linux hence I suggested to change partition type to FAT. Then format using

mkdosfs -I /dev/sda<n>

Mount it and copy data from your raid partition.


  1. Change /dev/sda to /dev/sdb or /dev/sdc whereever applicable
  2. FAT32 cannot take files of size greater then 4 GB.
  3. When you format using Linux FAT partitions can be of size > 32 GB, the Windows limit does not apply. The same partition would work in Windows without any problem.
  • There is a mkntfs program that claims to work. It might be worth looking into; I have not personally used it. linux.die.net/man/8/mkntfs – Michael Trausch Dec 19 '10 at 23:32
  • One big advantage of using FAT initially is that when you get into Windows, you can convert it to NTFS. – MikeyB Sep 5 '11 at 0:34

There shouldn't be any problems with doing it that way. I recommend when you are doing the change, boot into a LiveCD distribution and mount the old (ext3) partition as read only, format the new parition (NTFS), then copy your data.

This will leave you with a fresh untouched backup of your ext3 partition. Once you have windows installed, boot in and run a file utility checker on the files (simple checksums will do) run the same utility on your ext3 partition to verify no data has been changed during the migration and your good to go.

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