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I have two 500GB hard disk that were in a software RAID1 on a gentoo distribution. Now I have put the on an Ubuntu Server 10.10 and they still want to be in a RAID. How do I disable the RAID.

sudo mdadm --detail /dev/dm-1 mdadm: /dev/dm-1 does not appear to be an md device

sudo mdadm --stop /dev/dm-1 mdadm: /dev/dm-1 does not appear to be an md device

Device Boot Start End
Blocks Id System /dev/sdb1
1 60801 488384001 83 Linux

Disk /dev/sdd: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

Device Boot Start End Blocks Id System /dev/sdd1
1 60801 488384001 83 Linux

Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

Device Boot Start End Blocks Id System /dev/sdc1
1 60801 488384001 83 Linux

Disk /dev/dm-1: 500.0 GB, 499999965184 bytes 255 heads, 63 sectors/track, 60788 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000

 Device Boot      Start         End      Blocks   Id  System

/dev/dm-1p1 1
60801 488384001 83 Linux

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Can you show the output of 'cat /proc/mdstat' ? –  JooMing Nov 29 '10 at 15:17
    
cat /proc/mdstat >> " Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] unused devices: <none>" –  user61888 Nov 29 '10 at 15:46
2  
I think your disks know best. They used to be together.. They belong together. You can't just tear them apart. Disks have feelings too, y'know. –  Tom O'Connor Nov 29 '10 at 18:14
1  
@Tom overwrite the RAID superblock with a Converge song, drive will get over it better afterwards .... :) –  rackandboneman Dec 12 '12 at 8:06

2 Answers 2

You can make drives forget they were in a RAID by zeroing out their md superblocks. Assuming your old RAID drives are known as /dev/sdc and /dev/sdd in your Ubuntu system, try the following commands:

sudo mdadm --zero-superblock /dev/sdc
sudo mdadm --zero-superblock /dev/sdd

If, for whatever reason, those don't work, then you could try more drastic measures, like zeroing out the entire drives with dd, e.g.:

sudo dd if=/dev/zero of=/dev/sdc
sudo dd if=/dev/zero of=/dev/sdd

but I wouldn't try that unless nothing else worked, since it will take a relatively long time, and it will delete all data on those drives.

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sudo mdadm --zero-superblock /dev/sdc --> mdadm: Couldn't open /dev/sdc for write - not zeroing –  user61888 Nov 29 '10 at 16:02
    
Will "sudo dd if=/dev/zero of=/dev/sdc" make me lose data? –  user61888 Nov 29 '10 at 16:03
    
@user61888: Correct. The dd command will destroy all the data on the drive. If you want to keep your data, DO NOT do that. –  Steven Monday Nov 29 '10 at 16:16
1  
@user61888: Try this: Run sudo /etc/init.d/mdadm stop, then try sudo mdadm --zero-superblock /dev/sdc again. –  Steven Monday Nov 29 '10 at 16:26
    
Doesn't work either. It should be something from the harddisks themselves. They tried to be in a RAID array without me even installing mdadm. When I disconnect one of them BIOS tells me that there's a problem, F1- to continue. Then I can use the connected disk normally. When I connect both HDs they become an array, FUUUUU... –  user61888 Nov 29 '10 at 16:31

"dmraid -rE" did the trick. Removed the RAID array and everything is fine now.

Thank you everybody.

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