LinuxQuestions.org - How can I change super-minor number of a software raid array meta 1.2?

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How can I change super-minor number of a software raid array meta 1.2?

I had a double failure while I was away on the holidays of my array. As I was saving the data, I created a new array on a new drive has /dev/md1.

The original data was on an array listed created as /dev/md0, which I prefer.

How can I change my minor number of the raid back to /dev/md0? When it boots, it is recognized as /dev/md1.

I have read forums and tried various thing like updating assembling the array in this fashion to try to rewrite the superblock to no avail:

Code:

mdadm --assemble /dev/md0 --super-minor=0 --uuid=c35876ca:13e90c31:dc40c61c:eccfa279

Current array info:

Code:

dell-desktop ~ # mdadm -Es

ARRAY /dev/md/1 metadata=1.2 UUID=c35876ca:13e90c31:dc40c61c:eccfa279 name=dell-desktop:1

Code:

dell-desktop ~ # mdadm -E /dev/sdb6

/dev/sdb6:

          Magic : a92b4efc

        Version : 1.2

    Feature Map : 0x0

    Array UUID : c35876ca:13e90c31:dc40c61c:eccfa279

          Name : dell-desktop:1  (local to host dell-desktop)

  Creation Time : Mon Jan  6 19:44:05 2014

    Raid Level : raid1

  Raid Devices : 2



 Avail Dev Size : 1898729472 (905.38 GiB 972.15 GB)

    Array Size : 949364544 (905.38 GiB 972.15 GB)

  Used Dev Size : 1898729088 (905.38 GiB 972.15 GB)

    Data Offset : 262144 sectors

  Super Offset : 8 sectors

          State : clean

    Device UUID : 521142b5:2385b1b6:08f36e23:be4ae276



    Update Time : Tue Jan  7 13:57:21 2014

      Checksum : 19503e2a - correct

        Events : 575





  Device Role : Active device 1

  Array State : AA ('A' == active, '.' == missing)

Code:

dell-desktop ~ # cat /proc/mdstat 

Personalities : [raid1] 

md1 : active raid1 sda6[0] sdb6[2]

      949364544 blocks super 1.2 [2/2] [UU]

      

unused devices: <none>

Any help is kindly appreciated

Don't know if this is the proper technique to do it or not, but I modified my /etc/mdadm/mdadm.conf file to look like this:

Code:

dell-desktop ~ $ cat /etc/mdadm/mdadm.conf 

# mdadm.conf

#

# Please refer to mdadm.conf(5) for information about this file.

#

# by default (built-in), scan all partitions (/proc/partitions) and all

# containers for MD superblocks. alternatively, specify devices to scan, using

# wildcards if desired.

#DEVICE partitions containers



# auto-create devices with Debian standard permissions

CREATE owner=root group=disk mode=0660 auto=yes



# automatically tag new arrays as belonging to the local system

HOMEHOST <system>



# instruct the monitoring daemon where to send mail alerts

MAILADDR nathan.wood805@gmail.com



# definitions of existing MD arrays



# This file was auto-generated on Mon, 18 Feb 2013 16:52:46 -0600

# by mkconf 3.2.5-3

ARRAY /dev/md/1 metadata=1.2 UUID=c35876ca:13e90c31:dc40c61c:eccfa279 name=dell-desktop:1

Changing to this:

Code:

dell-desktop ~ $ cat /etc/mdadm/mdadm.conf 

# mdadm.conf

#

# Please refer to mdadm.conf(5) for information about this file.

#



# by default (built-in), scan all partitions (/proc/partitions) and all

# containers for MD superblocks. alternatively, specify devices to scan, using

# wildcards if desired.

#DEVICE partitions containers



# auto-create devices with Debian standard permissions

CREATE owner=root group=disk mode=0660 auto=yes



# automatically tag new arrays as belonging to the local system

HOMEHOST <system>



# instruct the monitoring daemon where to send mail alerts

MAILADDR nathan.wood805@gmail.com



# definitions of existing MD arrays



# This file was auto-generated on Mon, 18 Feb 2013 16:52:46 -0600

# by mkconf 3.2.5-3

ARRAY /dev/md0 metadata=1.2 UUID=c35876ca:13e90c31:dc40c61c:eccfa279 name=dell-desktop:1

When I rebooted, it was automatically assembled as /dev/md0. If there is a way to modify the superblock to make the minor number 0, I would prefer that, so if anyone has that solution, please post to this thread. I put the above technique in this thread so someone can get it to work at least this way.