Linux LVM.. Grub not loading from replaced disk

Linux and Unix-Like Ubuntu
1

Hi,

a little while ago, one of the GPT Partitioned hard disk had gone faulty in a Mirror RAID and is now successfully replaced.

here is how I did that.

1) created identical partition table on the new disk.
2) attached the mirrors using md commands.

The whole procedure is given below:

/dev/sda is replaced here

New Disk is replicated using sgdisk

sgdisk --replicate=/dev/sda /dev/sdb
sgdisk --randomize-guids --move-second-header /dev/sd

Created and Attached the mirrors to the raid system.

mdadm --manage /dev/md1 --add /dev/sda2
mdadm --manage /dev/md2 --add /dev/sda3
mdadm --manage /dev/md3 --add /dev/sda4

Now I have a good mirror in place. Now the question is that when I try to boot the system using the New Hard disk /dev/sda from the BIOS, it comes to halt and nothing shows up except blinking cursor on blank screen and I have to reboot the system to select the /dev/sdb disk to boot from. This is happening for the normal reboot as well, in such a way that i have to select the disk manually everytime the system is rebooted.

Can someone please guide how the other disk can be grub-recorgnized and how I can make a seamless reboot..

Below is the output from mdadmin --detail command

 mdadm --detail /dev/md{1..3}
/dev/md1:
        Version : 1.2
  Creation Time : Wed Jun  5 19:02:13 2013
     Raid Level : raid1
     Array Size : 19514240 (18.61 GiB 19.98 GB)
  Used Dev Size : 19514240 (18.61 GiB 19.98 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Sun Oct  6 01:00:02 2013
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           Name : busyboy:1  (local to host busyboy)
           UUID : 24d0bec2:c86a4b42:2551491c:ce21cac7
         Events : 50

    Number   Major   Minor   RaidDevice State
       0       8       18        0      active sync   /dev/sdb2
       2       8        2        1      active sync   /dev/sda2
/dev/md2:
        Version : 1.2
  Creation Time : Wed Jun  5 19:20:37 2013
     Raid Level : raid1
     Array Size : 488149824 (465.54 GiB 499.87 GB)
  Used Dev Size : 488149824 (465.54 GiB 499.87 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Thu Oct 10 13:47:44 2013
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           Name : busyboy:2  (local to host busyboy)
           UUID : ab235953:879428e8:d46af252:13ed66d3
         Events : 399197

    Number   Major   Minor   RaidDevice State
       0       8       19        0      active sync   /dev/sdb3
       2       8        3        1      active sync   /dev/sda3
/dev/md3:
        Version : 1.2
  Creation Time : Wed Jun  5 19:20:48 2013
     Raid Level : raid1
     Array Size : 2422320960 (2310.11 GiB 2480.46 GB)
  Used Dev Size : 2422320960 (2310.11 GiB 2480.46 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Thu Oct 10 13:47:46 2013
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           Name : busyboy:3  (local to host busyboy)
           UUID : 2a22160c:72b4f201:de0acb10:79566f08
         Events : 717493

    Number   Major   Minor   RaidDevice State
       0       8       20        0      active sync   /dev/sdb4
       2       8        4        1      active sync   /dev/sda4
2

Just guessing if this is sda, that perhaps it also holds the boot block? You'll need to copy that via some other mechanism. Again... just guessing...

3

Assuming you are using GRUB2, pre-EFI firmware, i.e. a BIOS, and a GPT disk, do you see any sign of a BIOS Boot Partition Table? Partition type should be EF02.

4

Hi,

i have created a Grub Partition on the disk drive as it recommended in a Guide

I have two 3 TB disks with mirroring. Is there anything related to creating the disk replication and then attaching it or something else?

Regards,
NMR

5

Did you populate the BIOS Boot Partition Table? Mirroring/replication is not going to do that for you.

6

hi,

Can you please suggest what that means to Populate the BIOS Partition. I'm not aware of this mechanism.

Regards,
Nasir

---------- Post updated Oct 22nd, 2013 at 01:52 PM ---------- Previous update was Oct 21st, 2013 at 06:37 PM ----------

Hi fpmurphy,

I have below given output from the gdisk command for the disk being replaced here.. both replaced and the good disk ( the disk which replicated its data to replaced one )

Disk /dev/sda: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 5B747213-253B-4BCD-9022-AC20F6A3EB6C
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 2925 sectors (1.4 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048            4095   1024.0 KiB  EF02  
   2            4096        39065599   18.6 GiB    FD00  
   3        39065600      1015627775   465.7 GiB   FD00  
   4      1015627776      5860532223   2.3 TiB     FD00  

Command (? for help): i
Partition number (1-4): 1
Partition GUID code: 21686148-6449-6E6F-744E-656564454649 (BIOS boot partition)
Partition unique GUID: 2B25F37D-4DCC-4D62-842A-322176A30AD9
First sector: 2048 (at 1024.0 KiB)
Last sector: 4095 (at 2.0 MiB)
Partition size: 2048 sectors (1024.0 KiB)
Attribute flags: 0000000000000000
Partition name: ' '

and below is the output for the disk ( which is intact till now and I replicated this disk to /dev/sda above )

Disk /dev/sdb: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 52E97A2C-D5CE-4FBE-8853-9A17F86DC779
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 2925 sectors (1.4 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048            4095   1024.0 KiB  EF02
   2            4096        39065599   18.6 GiB    FD00
   3        39065600      1015627775   465.7 GiB   FD00
   4      1015627776      5860532223   2.3 TiB     FD00

Command (? for help): i
Partition number (1-4): 1
Partition GUID code: 21686148-6449-6E6F-744E-656564454649 (BIOS boot partition)
Partition unique GUID: 95307A72-04D0-48A8-B676-FD04F74E1F62
First sector: 2048 (at 1024.0 KiB)
Last sector: 4095 (at 2.0 MiB)
Partition size: 2048 sectors (1024.0 KiB)
Attribute flags: 0000000000000000
Partition name: ' '